The correct answer is C) the Cabinet.
The group that serves directly under the president and heads the different executive departments is the Cabinet.
The Cabinet of the President of the United States is part of the Executive branch. It includes the Vice President and the heads of fifteen Executive Departments. The departments are the Education Department, Homeland Security Department, Defense Department, Commerce Department, State Department, Energy Department, Agriculture Department, Health Department, Interior, Housing and Urban Development, Veterans Affairs, Transportation Department, Labor Department, Treasury Department, and the Attorney General.