Final answer:
An executive agreement is a formal agreement between the President of the United States and another country's leader without legislative ratification, used for expedient foreign policy action. The correct option is (A).
Step-by-step explanation:
A executive agreement is an agreement between the President of the United States and the head of another country. It is a formal agreement that is not ratified by the legislature, unlike a treaty which requires ratification by a two-thirds majority in the Senate. Examples of executive agreements include the Vietnam War pacts and the North American Free Trade Agreement (NAFTA).
An example of an executive agreement is when the president signs legally binding nuclear arms terms with Iran without seeking congressional approval.
These agreements are considered enforceable as long as they do not conflict with current domestic law, and they can be a more expedient method for the president to conduct foreign policy. However, it's noteworthy that such agreements can be reversed by a subsequent president, making them less permanent than treaties.