Which of the following is a Cabinet-level position?

The Secretary of Education is a Cabinet-level position because this role is part of the President's Cabinet, which is a group of the most senior executive branch officials in the U.S. government. The Cabinet consists of the heads of the federal executive departments, and the Secretary of Education oversees the Department of Education, setting policies and ensuring they are enacted for the nation's schools. This position plays a critical role in shaping educational policy and managing federal education programs.

The Under Secretary of Defense, while an important role within the Department of Defense, is not considered a Cabinet-level position. Similarly, the Chief of Staff and the National Security Advisor are key advisors to the President but do not head departments that are part of the Cabinet. Therefore, the Secretary of Education distinctly qualifies as a member of the Cabinet, aligning with the structure and responsibilities typical of such positions in the U.S. government.