Final answer:
The correct addition to the list of government corporations is the Federal Reserve, which serves as the central bank of the United States and is involved in regulating the monetary system and the economy.
Step-by-step explanation:
The question pertains to the type of agencies within the U.S. federal government structure known as government corporations. Government corporations are entities created by the federal government to engage in commercial activities while providing a public service. The correct addition to the list of government corporations from the given options is a) the Federal Reserve.
The Federal Reserve, also known as the Fed, is the central bank of the United States and oversees the nation's monetary system, which includes regulating the nation's banks and conducting monetary policy to stabilize the economy. Unlike the FBI and CIA, which are independent executive agencies focused on national security and intelligence, and NASA, which is an independent executive agency dedicated to space exploration, the Federal Reserve functions like a government corporation in that it operates in the financial marketplace while serving public interests.