Article 9 of the GDPR prohibits the processing of special categories of personal data, which are data that reveal sensitive information about the data subject and may pose a high risk to their rights and freedoms. The GDPR defines 10 types of personal data as special categories, which are:
personal data revealing racial or ethnic origin;
personal data revealing political opinions;
personal data revealing religious or philosophical beliefs;
personal data revealing trade union membership;
genetic data;
biometric data (where used for identification purposes);
data concerning health;
data concerning a person's sex life; and
data concerning a person's sexual orientation.
Among the answer choices, only option C is not one of these categories, as financial data is not considered to reveal any sensitive information about the data subject. However, financial data is still subject to the general principles and rules of the GDPR, such as lawfulness, fairness, transparency, accuracy, security, etc. Reference:
Special category data | ICO
Art. 9 GDPR Processing of special categories of personal data
Special Categories of Data - International Association of Privacy Professionals