Which of the following is NOT a type of student pilot endorsement?

The Instrument Proficiency Endorsement is not a type of student pilot endorsement. This endorsement is specifically related to a pilot's proficiency in flying under instrument flight rules (IFR) and typically applies to those holding an instrument rating rather than to a student pilot.

In contrast, the other endorsements listed pertain directly to the privileges and limitations that are specific to student pilots. A Solo XC Endorsement allows a student to fly solo on cross-country flights, whereas a Solo at Night Endorsement authorizes a student to conduct solo flights during nighttime. The Repeated Solo XC Endorsement would be necessary when a student pilot needs to demonstrate proficiency on additional cross-country flights or after a certain period of not flying. Each of these endorsements serves to ensure that the student pilot meets the regulatory requirements for solo flight operations, whereas the Instrument Proficiency Endorsement goes beyond the scope of student pilot privileges.