Which PSI combines NAC with written inquiries to various organizations?

The correct answer is Access National Agency Check with Inquiries. This option represents a specific type of personnel security investigation that incorporates both a National Agency Check (NAC) and additional inquiries made to various organizations, allowing for a deeper understanding of an individual's background.

The NAC itself primarily focuses on federal records, checking for any criminal history or security concerns at the national level. By combining this with inquiries to local law enforcement agencies, employers, or other institutions (like current or former workplaces), the Access National Agency Check with Inquiries can provide a more comprehensive overview of an individual's trustworthiness and overall character.

This level of investigation is particularly significant for determining eligibility for access to classified information or sensitive positions, ensuring that individuals are vetted thoroughly beyond just a national overview. The incorporation of written inquiries allows for a personalized assessment, leading to more informed decisions in the hiring or security clearance process.