What principle requires that personal data must be processed lawfully, fairly, and transparently?

The correct answer is the legitimacy principle, which is foundational under the General Data Protection Regulation (GDPR). This principle mandates that personal data must be processed lawfully, fairly, and transparently, ensuring that individuals have a clear understanding of how their data is used. The legitimacy principle emphasizes that there needs to be a legitimate reason for processing an individual's personal data, such as consent, contract performance, legal obligation, vital interests, public tasks, or legitimate interests pursued by the data controller or a third party.

The other concepts, while important in the broader context of data protection, do not capture this specific requirement. The accountability principle refers to the obligation of organizations to demonstrate compliance with GDPR, not the fairness and transparency of data processing itself. The data minimization principle stipulates that only the necessary amount of data should be collected and processed, focusing more on the volume of data rather than the legality and fairness of processing. Finally, the fairness principle, while related to the manner in which data is processed, does not encapsulate the legal and transparent aspects highlighted in the legitimacy principle. Thus, the legitimacy principle is the correct framework under which these requirements are situated.