Which document verifies that a student pilot is eligible for training?

The correct answer provides crucial verification for a student pilot's eligibility for training. An unexpired foreign passport serves as a valid form of identification and confirms the student’s identity and citizenship status, which is necessary for compliance with regulatory requirements as a non-U.S. citizen seeking flight training in the United States.

In the context of training requirements, documentation like a valid U.S. pilot's certificate is relevant for licensed pilots but does not apply to student pilots, as they do not yet hold any pilot certification. A temporary flight instruction license does not exist in regulatory terms; student pilots typically do not receive a temporary license for initial training purposes. Lastly, although a certificate of U.S. citizenship confirms one’s nationality, it is not a document specifically tied to a student pilot’s eligibility for training in the same way that a passport is recognized and accepted.