Final answer:
Soldiers are not authorized to wear commercially purchased gray or black spandex shorts under the IPFU trunks, as per the Army's uniform policy.
Step-by-step explanation:
According to the military regulations that govern the wear and appearance of the Army uniform, soldiers are not authorized to wear commercially purchased gray or black spandex shorts under the Improved Physical Fitness Uniform (IPFU) trunks. The regulation stipulates that all components of the uniform should be free of any commercial logos visible when worn, and they should conform to the specifications listed in the Army's uniform policy. The appropriate undergarments should be of a neutral or skin-tone color so as not to be visible through the uniform, which generally means that no part of the commercial shorts would be permissible if visible.