Which of the following items is considered a type of identifier?

An identifier is a piece of information that can be used to uniquely distinguish an individual or entity. The date of birth serves as an important personal identifier because it is a specific piece of data that, when combined with other details like a name, can uniquely identify a person.

In various contexts, knowing an individual's date of birth can help confirm their identity, especially in processes such as verification for legal documents, financial transactions, healthcare services, and more. It is one of several identifiers that people often use to authenticate identity or access secure information.

While social security numbers, home addresses, and employee IDs are also types of identifiers, the specific context of the question implies a singular selection, in which the date of birth is a fundamental and commonly recognized identifier.