Final answer:
The President is responsible for ensuring that laws passed by Congress are enforced, as outlined by the executive power granted in the U.S. Constitution.
Step-by-step explanation:
Whose job was it to ensure laws passed by Congress were enforced? The correct answer is a) President. The Constitution of the United States assigns the executive power to the President. This means that the President is responsible for executing and enforcing the laws created by Congress. The executive branch, including the President and the Vice President, works alongside federal agencies to carry out this duty. It is essential to understand the separation of powers within the U.S. government, where the legislative branch (Congress) creates laws, the executive branch enforces them, and the judiciary (notably the Supreme Court) interprets them.
This structure ensures a system of checks and balances where, for example, the president can veto legislation and the Supreme Court can engage in judicial review, assessing the constitutionality of laws.