According to the Anti-Money Laundering Specialist (the 6th edition) by ACAMS, an institution's anti-money laundering program should be reassessed at least annually to ensure that it is current, effective, and compliant with the applicable laws and regulations. The reassessment should include a review of the institution's risk assessment, policies and procedures, internal controls, training, and independent testing. The reassessment should also consider any changes in the institution's products, services, customers, geographic locations, or business environment that may affect its exposure to money laundering and terrorist financing risks1.
The other options are not consistent with the best practices of maintaining an up-to-date anti-money laundering program. For example:
The program should be evaluated and updated at least every six months by the Board of Directors. While the Board of Directors has the ultimate responsibility for overseeing the institution's anti-money laundering program, it is not required to evaluate and update the program every six months. This may be too frequent and impractical, especially for large and complex institutions. The Board of Directors should, however, approve the program and any significant changes, and ensure that senior management implements and enforces the program effectively1.
The program should be reviewed by a federal law enforcement officer for gaps in controls. While federal law enforcement agencies may conduct investigations or examinations of the institution's anti-money laundering program, they are not responsible for reviewing the program for gaps in controls. This is the role of the institution's internal audit function or an external independent party, who should conduct periodic testing of the program's adequacy and effectiveness1.
The program should be sent to the institution's government regulator on a periodic basis. While the institution' s government regulator may request or review the institution's anti-money laundering program as part of its supervisory or enforcement activities, the institution is not obligated to send the program to the regulator on a periodic basis. The institution should, however, report any suspicious or unusual transactions or activities to the relevant authorities, such as the Financial Crimes Enforcement Network (FinCEN) or the Office of Foreign Assets Control (OFAC)1.
Anti-Money Laundering Specialist (the 6th edition) by ACAMS

According to the ACAMS CAMS Certification Study Guide (6th edition), a financial institution (FI) should update its ML/TF risk assessment when there are changes in its business activities, customer base, or operating environment that may affect its exposure to ML/TF risks1 Some examples of such changes are:
When new products, services or customer types are introduced: New products, services or customer types may introduce new or increased ML/TF risks that the FI may not have previously considered or addressed.
For example, offering online banking, prepaid cards, or cross-border remittances may create new opportunities for money launderers or terrorist financiers to exploit the FI's systems and processes. Therefore, the FI should assess the ML/TF risks associated with the new products, services or customer types and implement appropriate controls to mitigate them12 When the institution faces a merger or acquisition: A merger or acquisition may result in the FI inheriting the ML/TF risks of the other entity, as well as the potential liabilities and reputational damage that may arise from any ML/TF issues or violations. Therefore, the FI should conduct a due diligence on the other entity's ML/TF risk assessment, policies, procedures, and controls, and identify any gaps or weaknesses that need to be addressed. The FI should also integrate and harmonize the ML/TF risk assessment and compliance programs of the merged or acquired entity with its own13
1: ACAMS CAMS Certification Study Guide (6th edition), page 32. 2: Money laundering/terrorism financing risk assessment | AUSTRAC4 3: MONEY LAUNDERING & TERRORIST FINANCING (ML/TF) RISK ASSESSMENT METHODOLOGY5, page 4.
Reference: https://www.fatf-gafi.org/media/fatf/content/images/National_ML_TF_Risk_Assessment.pdf

This is when a customer or a transaction does not provide sufficient or credible information about their identity, source of funds, business activity, or purpose of the transaction. Lack of transparency can indicate that the customer or the transaction is trying to conceal the origin, ownership, or destination of illicit funds, or to evade regulatory scrutiny or reporting obligations. Lack of transparency is a common risk factor for money laundering and terrorist financing, especially in high-risk jurisdictions or sectors.
The other options are not necessarily red flags, although they may increase the risk or require further due diligence depending on the circumstances and the risk profile of the customers and countries involved. Option A describes a referral by a longtime friend of the dealer, which may be a legitimate source of trust or business relationship, but it does not substitute the need for proper customer identification and verification. Option B describes the location of the precious metals dealer, which may be a high-risk jurisdiction due to factors such as weak governance, corruption, crime, or sanctions, but it does not imply that the dealer or the customer is involved in money laundering. Option C describes the amount and nature of the transaction, which may be unusual or large, but it does not necessarily indicate money laundering, as long as the customer can provide a reasonable explanation and evidence for the source and use of funds.
ACAMS CAMS Certification Video Training Course - 6th Edition1
Exam CAMS: Certified Anti-Money Laundering Specialist (the 6th edition)2 ACAMS CAMS Study Guide - 6th Edition, Chapter 3, pages 64-65
https://www.acams.org/wp-content/uploads/2019/09/ACAMS-CAMS-Study-Guide-6th-Edition-Chapter-3.pdf

According to the ACAMS Study Guide 6th Edition, Chapter 2, page 37, one of the red flags of money laundering or terrorist financing is the use of nominees, trusts, or third parties to hide the identity, ownership, or control of the funds or assets involved in the transaction. Nominees are individuals or entities that act on behalf of the actual or beneficial owners of a company, trust, or account, and may be used to conceal the source, destination, or purpose of the funds or assets. Nominees may also be used to evade taxes, sanctions, or regulatory requirements.
In this case, the compliance officer is unable to verify the identity of the beneficial owners of the company, and only information on the nominee owners was provided. This raises the suspicion that the company may be involved in money laundering or terrorist financing activities, and that the nominee owners may be acting as fronts or intermediaries for the actual or beneficial owners. The compliance officer should conduct further due diligence on the company, the nominee owners, and the beneficial owners, and report any suspicious or unusual activity to the relevant authorities.
ACAMS Study Guide 6th Edition, Chapter 2, page 37
Beneficial Ownership Meaning and Regulation - Investopedia
What is a nomineeshareholder? | LawBite

International cooperation is essentialinAML investigations, and theEgmont GroupfacilitatesFIU-to-FIU information sharing.
Option D (Correct):Egmont Group memberscan request and share information forAML/CFT investigations.
Option A (Incorrect):Sovereigntydoes not preventcooperationunder proper agreements.
Option B (Incorrect):AML laws allowdata sharing under legal frameworkslikeMutual Legal Assistance Treaties (MLATs).
Option C (Incorrect):Information sharing isrestricted to FIUs and authorized agencies, notall organizations.
Reference:FATF Recommendation 40 (International Cooperation), Egmont Group FIU Guidelines, Mutual Legal Assistance Treaties (MLATs).