Final answer:
An executive order is most similar to a law and is a directive by the President that has the force of law within the federal government. It differs from a court decision, an amendment, and a proposal in that it is legally binding but does not require congressional approval.
Step-by-step explanation:
An executive order is most similar to a law (c). This is because it is a directive issued by the President that has the force of law, meant to manage operations within the federal government. Unlike a law passed by Congress, an executive order does not require congressional approval, but it is still legally binding on the agencies and individuals affected by it. Comparatively, a court decision is a judgment made by the judiciary; an amendment is a formal change to the Constitution; and a proposal is simply a suggestion put forth that has no legal standing unless adopted.
Executive orders have played significant roles in history, with some examples including the Emancipation Proclamation by Lincoln and the desegregation of the armed forces by Truman. They typically involve reorganization within the executive branch or imposing certain directives on bureaucracies.