Which of the following is an example of personal data?

The identification of an email address of an individual as personal data is accurate due to the fact that it pertains to an identifiable individual. Personal data is any information that relates to an identified or identifiable natural person, also known as a data subject. An email address can be used to contact someone directly and can often be linked to that person’s identity, making it personal data under privacy laws such as the General Data Protection Regulation (GDPR) and various U.S. privacy frameworks.

In contrast, the other options do not qualify as personal data. The number of employees in a company is aggregate data related to the organization and does not pertain to individual identification. Company revenue figures are also organizational data, and while it may provide insights into the business's performance, it does not relate to any specific individual. Similarly, publicly available data on businesses relates to the entity itself rather than any natural person, thus failing to meet the definition of personal data.