Final answer:
AR 385-10 states that a full-face helmet is an approved motorcycle helmet.
Step-by-step explanation:
The AR 385-10 is a regulation in the United States Army that addresses safety regulations, including those related to motorcycle helmets. In order to be an approved helmet, it must meet certain requirements.
An approved motorcycle helmet according to AR 385-10 is a full-face helmet. These helmets cover the entire head, including the face, and provide the most protection in the event of a crash.
Therefore, the correct answer to the question is 1) Full-face helmet.