Final answer:
The required grade/rank for the inventory officer overseeing quarterly inventory of AFWCF/MDD-owned Controlled items is O-2 or GS-7, ensuring they possess the necessary responsibility and expertise.
Step-by-step explanation:
The grade or rank required for the disinterested inventory officer conducting a quarterly inventory of AFWCF/MDD-owned Controlled items is Option A: O-2 or GS-7. The inventory officer must hold a minimum rank of an O-2, which is a First Lieutenant in the military, or a civilian grade of GS-7 within the General Schedule (GS) used to classify civilian employees in the federal government. This ensures that the officer has a sufficient level of responsibility and expertise to manage the inventory effectively and conduct it with the appropriate level of oversight.