Which of the following should be excluded from an employee's personnel file for privacy reasons?

The correct choice pertains to the protection of sensitive personal information, particularly medical-related data. Medical benefits claims data is considered highly confidential and is protected under various regulations, including the Health Insurance Portability and Accountability Act (HIPAA). This legislation mandates strict controls over the handling and sharing of medical information to ensure an individual's privacy.

In contrast, the other items listed, such as applications for employment, historical records, and performance reviews, do not carry the same level of sensitivity regarding personal health information. While applications for employment and performance reviews can contain personal information, they do not typically pose the same risks associated with the direct identification of medical issues or claims. Historical records, depending on the context, may also include data that is less sensitive and more relevant to employment history rather than personal health. Thus, in consideration of privacy and confidentiality laws, medical benefits claims data is the most appropriate item to exclude from an employee's personnel file.