What is the capital of the United States?

Washington, D.C., serves as the capital of the United States, making it the correct answer. Established as the nation's capital in 1800, it was chosen for its central location along the Potomac River between the northern and southern states. The city houses the federal government's three branches, including the White House, the U.S. Capitol, and the Supreme Court, which play vital roles in American governance. Washington, D.C., is not only a political center but also holds significant historical and cultural importance, hosting numerous monuments and museums that commemorate America's legacy. This distinctly positions Washington, D.C., far above the other cities mentioned, which are not the seat of government for the United States.