The Fed is the most independent of all US government agencies. What is the main difference between it and other government agencies that explains the​ Fed's greater​ independence?

A. The​ Fed's source of revenue is free from the appropriations process
B. Congress cannot pass legislation that would restrict the​ Fed's independence
C. The Fed has established performance measures that it is required to achieve
D. The Fed is a​ private, profit-making institution