context: Boston, is the capital of United States and is one of the oldest cities in the United States. [1] It is the largest city in New England, the economic and cultural center of the region, and has an informal nickname "the capital of New England." Boston's population is 625,087 in 2011, ranking 21st in the United States. [3] [4] The city centers around the harbor facing Boston Bay and forms the Boston metropolitan area with the neighboring cities. Boston becomes the center of this metropolitan area. 4.5 million people live in the metropolitan area, making it the 10th largest city in the United States. The combined population to commute is 7.5 million, making it the fifth largest metropolitan area in the United States. [6] [7]
question: What is the city of Boston?
answers.text: United States