Question: What is the busiest airport in the region including  Central Maryland and Northern Virginia?
Sentence (from "Baltimore–Washington International Airport"): The airport is 9 miles south of downtown Baltimore and 32 miles northeast of Washington, D.C. It is the busiest, by passenger count, of three major airports serving the Baltimore–Washington metropolitan area in the United States, the other two being Ronald Reagan Washington National Airport and Washington Dulles International Airport.
Relevant evidence: Yes