Which of the following departments is NOT a cabinet-level office?

The Department of Education, Department of Energy, and Department of Transportation are all cabinet-level offices that play significant roles in the executive branch of the U.S. government, reporting directly to the President. These departments are involved in managing specific areas of federal administration and policy, such as education policy, energy resources, and transportation infrastructure.

In contrast, an Independent Regulatory Commission operates independently of the executive departments and is not part of the President's cabinet. These commissions, such as the Federal Communications Commission (FCC) or the Securities and Exchange Commission (SEC), are established by Congress to enforce regulations in particular sectors. They are designed to be insulated from presidential influence to ensure they can carry out their regulatory functions without political pressure, which distinguishes them from cabinet-level offices.