Answer: c) The longer terms are to insulate the members from immediate political pressures and have them focus solely on economic solutions for the nation.
Step-by-step explanation:
The Fed is independent of the U.S. Government but can still face significant pressure from the U.S. Government as it is the President that nominates the Board of Governors and the Senate confirms them.
Much like Justices on the Supreme Court who get their positions the same way, these governors have to be protected from being used as political pawns so they are given long terms in office to ensure that they can pursue an independent policy without having to worry about the current administration coming after them if they go contrary to its will.