What is the capital of the United States?

Why this is the answer

The capital of the United States is Washington, D.C., where the federal government does its business. It was not the first capital: the new government met in New York City in 1789 and then in Philadelphia, while a permanent capital was built on land along the Potomac River between Maryland and Virginia, a site chosen by George Washington. The government moved there in 1800. D.C. stands for District of Columbia; it is not part of any state. Memory hook: the capital is named after the first President.