A technical vulnerability assessment on a personnel information management server should be performed when:

 A technical vulnerability assessment is a process of identifying and evaluating the weaknesses and risks associated with a specific system, component, or network. A technical vulnerability assessment can help to determine the potential impact and likelihood of a security breach, as well as the appropriate measures to prevent or mitigate it. A technical vulnerability assessment should be performed on a personnel information management server whenever there is an increase in the number of unauthorized access attempts to the server, as this indicates that the server may have been compromised or targeted by an attacker12. Therefore, option C is the correct answer. References =

CISM Review Manual (Digital Version), Chapter 5: Information Security Program Management

CISM Review Manual (Print Version), Chapter 5: Information Security Program Management