Which of the following data points is considered personally identifiable information (PII)?

An email address is considered personally identifiable information (PII) because it can be used to identify or contact an individual. PII encompasses any data that can be used to distinguish or trace an individual's identity, either alone or when combined with other personal information. An email address specifically serves as a means of direct communication and can often be linked to an individual’s identity, making it sensitive and requiring protection under various privacy laws and regulations.

While the other options, such as a diagnosis, credit card number, and medical record number, also contain sensitive information, they can have different categorizations depending on the context and applicable regulations. For example, a credit card number is financial information, and while it is highly sensitive, it typically does not directly identify a person without additional context. A medical record number specifically relates to healthcare but not necessarily to personal identification without further connection to an individual.