Which of the following is the biggest office in the executive office of the president?
a. the council on economic advisors
b. the office of management and budget
c. the national security council
d. the office of administration

C. the National Security Council 

Which of the following is the biggest office in the Executive Office of the President?
the National Security Council 

NOT:

A. the Council on Economic Advisors 
B. the Office of Management and Budget 
D. the Office of Administration