Which of the following is NOT a Cabinet-level position?

The Chief Justice of the Supreme Court is not a Cabinet-level position, as the role of the Chief Justice pertains specifically to the judicial branch of the government. The Cabinet, on the other hand, is composed of members who head the executive departments and serve as advisors to the President. The other positions listed, including the Secretaries of Commerce, Defense, and Agriculture, are all part of the President's Cabinet, responsible for overseeing their respective departments and implementing federal policies within their areas of expertise. Each of these roles directly assists the President in executing federal laws and managing the government, which distinctly separates them from judicial positions like that of the Chief Justice.