What type of vessel is not armed and carries blue and gold striping on ship stacks?

The correct answer is that a United States Naval Ship (USNS) is not armed and typically carries blue and gold striping on its ship stacks. USNS vessels are part of the Navy's Military Sealift Command and are primarily used to provide logistic support to the Navy and other branches of the armed forces. Unlike combat ships that are designed for warfare, USNS ships serve purposes such as transporting supplies, fuel, and personnel, and do not possess weapons or engaging capabilities.

The blue and gold striping on the stacks of a USNS vessel serves as an identification feature that distinguishes them from other naval ships. This color scheme is an indication of its purpose and mission rather than a function of military combat.

The other types of vessels mentioned in the other options, such as aircraft carriers, destroyers, and submarines, are armed and designed for combat operations. They are equipped with various weapon systems and technologies to engage in naval warfare, which differentiates them fundamentally from the USNS structure.