What year was the Constitution ratified?

The Constitution was ratified in 1788, making this the correct answer. Ratification is the process by which a proposed law or constitution is formally approved and adopted. In the case of the United States Constitution, it was drafted in 1787 during the Constitutional Convention and subsequently sent to the states for ratification. By June 21, 1788, with the approval of New Hampshire, the Constitution received the necessary nine out of thirteen state ratifications to become effective.

The other years mentioned are significant in American history but are related to different events. For instance, 1776 marks the year of the Declaration of Independence, where colonies declared their freedom from British rule. In 1781, the Articles of Confederation, the first governing document of the United States, were ratified. Finally, 1791 is notable for the ratification of the Bill of Rights, which are the first ten amendments to the Constitution, but not the Constitution itself. This context illustrates why 1788 is the accurate year for the Constitution's ratification.