Which classes of excess items are not authorized for return? (Select three that apply)

The correct answer identifies certain classes of excess items that are not authorized for return. Class I perishable subsistence items, which include food and perishables essential for military operations, cannot be returned due to their short shelf life and the necessity for them to be consumed in a timely manner. Class VIII medical items, consisting of medical supplies and equipment, often have stringent handling requirements and expiration dates, making their return problematic once issued. Lastly, Class II CBRN items, which pertain to chemical, biological, radiological, and nuclear defense, typically have strict regulations around their handling and distribution, preventing return once they are issued.

The other options contain classes of items that may have different return protocols. Class V ammunition, while highly regulated, can sometimes be returned under specific conditions. Class III fuel items and Class VII repair parts typically undergo evaluations to determine their returnability based on their condition and need within military operations. This variability allows for certain classifications of excess items to be returned if deemed appropriate, in contrast to the rigid restrictions placed on the selected classes in the correct answer.