What is the general purpose of personnel security investigations?

The general purpose of personnel security investigations is to determine an individual's eligibility for a security clearance. This process is critical within the context of national security and the protection of sensitive information. Investigations assess an applicant's background, character, and reliability, among other factors. The goal is to discern whether an individual can be trusted to access classified or sensitive information based on their past behaviors and associations.

In the context of personnel security, having the correct investigations ensures that individuals who are granted access to sensitive information will act in a manner that upholds national security interests. This includes looking into financial history, criminal records, and personal conduct, which collectively help in making an informed decision regarding an individual's fitness for a security clearance.

The other options, while relevant in broader security contexts, do not reflect the primary aim of personnel security investigations. Training security personnel, ensuring compliance with safety standards, and assessing organizational expenditures serve different purposes that do not specifically focus on the eligibility of individuals for security clearances. Thus, option C is the most accurate answer reflecting the intent of personnel security investigations.