Which source of supply provides wholesale support to all government agencies?

The General Services Administration (GSA) is the correct answer because it serves as the primary source of supply that provides wholesale support to all federal government agencies. The GSA plays a crucial role in procurement, ensuring that government entities have access to a wide range of products and services efficiently and economically. It acts as a centralized procurement authority that streamlines processes and leverages the government's purchasing power to get favorable prices and terms.

In addition to offering procurement support, the GSA manages federal buildings, real estate, and technology, along with providing policy support and oversight in areas of federal contracting. This broad scope of services ensures that all government agencies can operate effectively while adhering to federal regulations and standards.

Other sources listed, such as the Department of Defense (DOD) and the Defense Logistics Agency (DLA), primarily focus on military logistics and supply chain functions and support specifically for defense-related activities. The Army and Air Force Exchange Service (AAFES) operates primarily as a retail entity providing goods and services to military personnel and their families. Therefore, these organizations do not fulfill the overarching role of providing wholesale support to all government agencies like the GSA does.