Final answer:
The description that matches an executive power of the president is 'C. Using executive orders to send instructions to executive agencies and departments.' option C is correct answer.
Step-by-step explanation:
Among the options provided, C. Using executive orders to send instructions to executive agencies and departments describes an executive power of the president. Executive orders are rules or instructions issued by the president to federal agencies that do not require Congressional approval but still carry the force of law, provided they are not invalidated by the courts. These are tools the president uses to manage the operations of the federal government and direct the behavior of the bureaucracy.
Option A, Issuing amnesty, is indeed a presidential power, but it's more specifically associated with the president's power to grant reprieves, pardons, and amnesty. Option B, Vetoing legislation, while certainly an executive power, represents the president's legislative power rather than executive. Lastly, Option D, Pushing their agenda in the State of the Union address, is a presidential action but not primarily an executive power as it's akin to a recommendation and a communication tool.
Presidents also engage in other executive actions such as appointing officials, ensuring that laws be faithfully executed, and wielding executive power in foreign policy through informal executive agreements with other nations.