Answer:
B. Once diverted to the alternate airport,you may fly a GPS-based approach as long as there is an operational ground-based NAVAID and appropriate airborne receiver for use as a backup.
Explanation:
As stated in the question, If someone is on-board GPS-based FMS/RNAV unit, and the destination is the minimum target, it is obvious that once diverted to the alternate airport,you may fly a GPS-based approach as long as there is an operational ground-based NAVAID and appropriate airborne receiver for use as a backup. The correct answer is option B.