Explanation
Irreversible disposal is a process of removing or destroying data from a storage device or media to prevent unauthorized access or recovery of the data. Irreversible disposal is the most important thing to establish within a data storage policy to protect data privacy, as it reflects the principles of data minimization and storage limitation, which require limiting the collection, storage and processing of personal data to what is necessary and relevant for the intended purposes, and deleting or disposing of personal data when it is no longer needed or justified. Irreversible disposal also helps to reduce the privacy risks and costs associated with data storage and retention, such as data breaches, unauthorized access, misuse or loss of data. The other options are not as important as irreversible disposal in protecting data privacy within a data storage policy.
Data redaction is a technique that removes or obscures sensitive or confidential information from a document or file, but it does not address the issue of data retention or deletion. Data quality assurance (QA) is a process of ensuring that the data meets the standards and specifications of accuracy, completeness, consistency and reliability, but it does not address the issue of data retention or deletion. Collection limitation is a principle that requires limiting the collection of personal data to what is necessary and relevant for the intended purposes, but it does not address the issue of data retention or deletion1, p. 75-76 References: 1: CDPSE Review Manual (Digital Version)

Explanation
Asymmetric encryption is a method of encrypting and decrypting data using two different keys: a public key and a private key. The public key can be shared with anyone, while the private key is kept secret by the owner.
Data encrypted with the public key can only be decrypted with the private key, and vice versa. Asymmetric encryption ensures the security of encryption keys when transferring data containing personal information between cloud applications, by providing the following benefits:
* It can prevent unauthorized access or use of the data, as only the intended recipient who has the matching private key can decrypt the data sent by the sender who has the public key.
* It can prevent man-in-the-middle attacks, where an attacker intercepts and modifies the data or keys in transit, as any tampering with the data or keys will result in decryption failure or error.
* It can enable digital signatures, where the sender encrypts a message digest of the data with their private key, and the recipient verifies it with the sender's public key. Digital signatures can ensure the authenticity and integrity of the data and the sender.
The other options are less effective or irrelevant for ensuring the security of encryption keys when transferring data containing personal information between cloud applications. Whole disk encryption is a method of encrypting all the data on a disk or device, such as a laptop or a smartphone. It does not protect the data when they are transferred over a network or stored on a cloud server. Symmetric encryption is a method of encrypting and decrypting data using the same key. It requires both parties to securely exchange and store the key, which may be difficult or risky in a cloud environment. Digital signature is not a method of encryption, but an application of asymmetric encryption that can provide additional security features for data transmission.

Explanation
A privacy impact assessment (PIA) is a systematic process of identifying and evaluating the potential privacy risks and impacts of a data processing activity or system. A PIA helps to ensure that privacy is considered and integrated into the design and development of data processing activities or systems, and that privacy risks are mitigated or eliminated. A PIA also helps to determine the appropriate retention periods for personal data based on the purpose and necessity of the data processing, as well as the legal and regulatory obligations that apply to the data. Therefore, a PIA helps to define data retention time in a stream-fed data lake that includes personal data. References: : CDPSE Review Manual (Digital Version), page 99

Explanation
The best way for an organization to ensure its vendors are complying with data privacy requirements defined in their contracts is to obtain independent assessments of the vendors' data management processes, because this will provide an objective and reliable evaluation of the vendors' privacy practices, policies, and controls.
Independent assessments can be performed by external auditors, consultants, or certification bodies that have the expertise and credibility to verify the vendors' compliance with the contractual obligations and expectations. Independent assessments can also help identify and address any privacy risks or gaps that may arise from the vendors' processing of personal data12.
References:
* CDPSE Exam Content Outline, Domain 1 - Privacy Governance (Governance, Management & Risk Management), Task 7: Participate in the management and evaluation of contracts, service levels and practices of vendors and other external parties3.
* CDPSE Review Manual, Chapter 1 - Privacy Governance, Section 1.4 - Third-Party Management4.

Explanation
The best indication of a highly effective privacy training program is that members of the workforce understand their roles in protecting data privacy, because this shows that the training program has successfully raised the awareness and knowledge of the workforce on the importance, principles and practices of data privacy, and how they can contribute to the organization's privacy objectives and compliance. According to ISACA, one of the key elements of a privacy training program is to define and communicate the roles and responsibilities of the workforce in relation to data privacy1. Members of the workforce who understand their roles in protecting data privacy are more likely to follow the privacy policies and procedures, report any privacy incidents or issues, and support the privacy culture of the organization2. Recent audits have no findings or recommendations related to data privacy, no privacy incidents have been reported in the last year, and HR has made privacy training an annual mandate for the organization are not as reliable as members of the workforce understand their roles in protecting data privacy, as they do not necessarily reflect the effectiveness of the privacy training program, but rather the performance of other factors such as audit processes, incident management systems, or HR policies.