The Office of Foreign Assets Control (OFAC) is a department of the US Treasury that administers and enforces economic and trade sanctions imposed by the US against countries and groups of individuals, such as terrorists and narcotics traffickers. The sanctions can be either comprehensive or selective, using the blocking of assets and trade restrictions to accomplish foreign policy and national security goals. The main purpose of the US Treasury Department for OFAC's extraterritorial reach is to apply these sanctions to any person or entity that is subject to US jurisdiction, or that engages in transactions involving US persons, US dollars, or US goods or services. This way, the US can exert pressure on the targets of the sanctions and prevent them from accessing the US financial system or market. OFAC's extraterritorial reach is authorized by Congressional legislation or presidential emergency powers, and is often based on UN Security Council resolutions or multilateral agreements.
References:
Office of Foreign Assets Control (OFAC): Definition, Sanctions
About OFAC | Office of Foreign Assets Control
OFAC's Extraterritorial Reach: Purpose of the US Treasury Department
Reference:
https://www.natlawreview.com/article/aggressive-extraterritorial-reach-us-economic-sanctions-foreign-company

a vehicle that is historically most often used to hide beneficial ownership, which is an offshore company. An offshore company is a legal entity that is incorporated or registered in a foreign jurisdiction, usually with low or no taxes, high confidentiality, and lax regulation. Offshore companies can be used by money launderers and other criminals to conceal the true identity and ownership of the funds or assets that they control, and to evade taxes, reporting, or legal obligations in their home jurisdictions. Offshore companies can also be layered with other vehicles, such as trusts, foundations, or nominees, to create complex and opaque structures that make it difficult for authorities to trace the source and destination of illicit funds.
The other options are not necessarily vehicles that are most often used to hide beneficial ownership, although they may pose some risks or challenges depending on the circumstances and the risk profile of the customers and countries involved. Option A describes a professional association, which is a group of individuals or entities that share a common profession or interest, such as lawyers, accountants, or doctors. Professional associations may be involved in money laundering or terrorist financing as facilitators, intermediaries, or advisors, but they are not typically used to hide beneficial ownership. Option C describes a limited liability partnership, which is a legal entity that combines the features of a partnership and a corporation, and limits the liability of its partners. Limited liability partnerships may be used by money launderers or terrorist financiers to obscure the ownership or control of funds or assets, but they are not as common or as secretive as offshore companies. Option D describes a charitable organization, which is a non-profit entity that is established for a charitable, religious, educational, or other public benefit purpose. Charitable organizations may be abused by money launderers or terrorist financiers to divert funds or assets for illicit purposes, but they are not usually used to hide beneficial ownership.
References:
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 4, pages 86-87
https://www.acams.org/wp-content/uploads/2019/09/ACAMS-CAMS-Study-Guide-6th-Edition-Chapter-4.pdf