Answer:
The answer is D, Congress makes laws, and the president ensures
they are carried out.
Explanation:
With the department of state (foreign affairs) being in the executive branch of government that answers/falls under the President, I would conclude that C is incorrect.
With the department of homeland security (domestic affairs) being in the executive branch of government that answers/falls under the President, I would conclude that A is incorrect.
With congress being the legislative branch of gov, I would conclude that B is incorrect.
Therefore, remaining is answer D.