Which of these statements accurately describes the Merchant Marine?

The statement indicating that in wartime, the Merchant Marine serves as the primary carrier of supplies and personnel for the armed services is accurate. The Merchant Marine plays a crucial role in logistical support during military operations by transporting cargo, fuel, and troops necessary for sustaining military activities. This function allows the armed services to maintain effective operations without relying exclusively on military vessels, thus expanding their logistical capabilities.

The other statements describe responsibilities that do not align directly with the primary roles of the Merchant Marine. While port security and search and rescue are vital maritime functions, they are typically managed by the Coast Guard or similar agencies. Similarly, the maintenance and repair of facilities and equipment are responsibilities of specialized military or civilian contractors, and the maintenance of navigation aids like lighthouses and buoys is primarily a task for the Coast Guard or local maritime authorities. Hence, the correct choice highlights the specific and significant wartime function of the Merchant Marine in supporting military logistics.