The primary reason to complete a privacy impact assessment (PIA) is to understand privacy risks associated with the collection, use, disclosure or retention of personal data. A PIA is a systematic process to identify and evaluate the potential privacy impacts of a system, project, program or initiative that involves personal data processing activities. A PIA helps to ensure that privacy risks are identified and mitigated before the implementation is executed. A PIA also helps to ensure compliance with privacy principles, laws and regulations, and alignment with customer expectations and preferences. The other options are not primary reasons to complete a PIA. To comply with consumer regulatory requirements may be a reason to complete a PIA, but it is not the primary reason, as consumer regulatory requirements may vary depending on the context and jurisdiction. To establish privacy breach response procedures may be an outcome of completing a PIA, but it is not the primary reason, as privacy breach response procedures are only one aspect of mitigating privacy risks. To classify personal data may be an activity that is part of completing a PIA, but it is not the primary reason, as personal data classification is only one aspect of understanding privacy risks1, p. 67 Reference: 1: CDPSE Review Manual (Digital Version)

Reference:
Data masking is a technique that replaces sensitive or confidential data with realistic but fictitious data, such as random characters or numbers, to prevent unauthorized access or disclosure of the original data. Data masking is the best way to hide sensitive personal data that is in use in a data lake, as it would protect the privacy of the data subjects by reducing the linkability of the data set with their original identity, and also comply with the data minimization principle that requires limiting the collection, storage and processing of personal data to what is necessary and relevant for the intended purposes. Data masking would also preserve some characteristics or patterns of the original data that can be used for analysis or research purposes, without compromising the accuracy or quality of the results. The other options are not as effective as data masking in hiding sensitive personal data that is in use in a data lake. Data truncation is a technique that removes some portions of data from a document or file, such as digits from a credit card number or characters from an email address, to prevent unauthorized access or disclosure of the original data, but it may affect the accuracy or quality of the analysis or research results, as some characteristics or patterns of the original data may be lost or distorted. Data encryption is a technique that transforms plain text data into cipher text using an algorithm and a key, making it unreadable by unauthorized parties, but it does not reduce the linkability of the data set with the original identity of the data subjects and may require additional security measures to protect the encryption keys or certificates. Data minimization is a principle that requires limiting the collection, storage and processing of personal data to what is necessary and relevant for the intended purposes, but it does not address how to hide sensitive personal data that is already in use in a data lake1, p. 74-75 Reference: 1: CDPSE Review Manual (Digital Version)

The data controller determines the purposes and means of processing and therefore retains primary accountability for risk-even if a processor or custodian executes processing. Data processors (C) act under instructions; custodians (A) safeguard data but do not define processing; data scientists (B) are operational users, not accountable owners.
"The data controller remains accountable for compliance and risk regardless of outsourcing processing activities."

Senior leadership must define the roles and responsibilities of the person with oversight, who is responsible for ensuring compliance with the data privacy policy and applicable laws and regulations. This person may also be known as the data protection officer, the privacy officer, or the chief privacy officer, depending on the organization and jurisdiction. The person with oversight should have the authority, resources, and independence to perform their duties effectively.
Reference:
ISACA, CDPSE Review Manual 2021, Chapter 2: Privacy Governance, Section 2.1: Privacy Governance Framework, p. 35-36.
ISACA, Data Privacy Audit/Assurance Program, Control Objective 1: Data Privacy Governance, p. 4-51

The best testing method to identify and review the application's runtime modules is dynamic application security testing (DAST). DAST is a testing technique that analyzes the application's behavior and functionality during its execution. DAST can detect security and privacy vulnerabilities that are not visible in the source code, such as injection attacks, cross-site scripting, broken authentication, sensitive data exposure, or improper error handling. DAST can also simulate real-world attacks and test the application's response and resilience. DAST can provide a comprehensive and realistic assessment of the application's security and privacy posture in the pre-production environment. Reference:
[ISACA Glossary of Terms]
[OWASP Top 10 Web Application Security Risks]
[ISACA CDPSE Review Manual, Chapter 2, Section 2.4.2]
[ISACA Journal, Volume 6, 2018, "Dynamic Application Security Testing"]