Question: WBTJ serves which independent city in the U.S. state of Virginia?
Context: Warwick is an extinct independent city which was located in the State of Virginia in the United States from 1952 until 1958.  Formed by a political conversion of the former Warwick County, Virginia (1634–1952), it is now part of the independent city of Newport News, Virginia. U.S. Route 33 (US 33) is a part of the U.S. Highway System that runs from Elkhart, Indiana to Richmond, Virginia.  In Virginia, the U.S. Highway runs 135.60 mi from the West Virginia state line near Rawley Springs east to its eastern terminus at SR 33 in Richmond.  US 33 is the primary east–west highway of Rockingham County, which lies in the Shenandoah Valley.  The highway connects the independent city of Harrisonburg (which also serves as the seat of Rockingham County), the town of Elkton, and an entrance to Shenandoah National Park.  East of the Blue Ridge Mountains, US 33 connects the Piedmont communities of Stanardsville, Gordonsville, and Louisa.  The U.S. Highway is a major suburban and urban route in the Richmond metropolitan area.  Within Richmond, US 33 runs concurrently with US 250.  SR 33 continues from US 33's eastern terminus as a state-numbered extension of the U.S. Highway that connects Richmond with Virginia's Middle Peninsula. State Route 143 (SR 143) is a primary state highway in the U.S. state of Virginia.  The state highway runs 35.39 mi from Camp Peary near Williamsburg east to U.S. Route 258 (US 258) at Fort Monroe in Hampton.  SR 143 is a major local thoroughfare on the Virginia Peninsula portion of the Hampton Roads metropolitan area.  The state highway is named Merrimac Trail through the independent city of Williamsburg and adjacent portions of York County and James City County.  SR 143 follows Jefferson Avenue through the city of Newport News from the Williamsburg area past Newport News/Williamsburg International Airport to near Downtown Newport News.  The state highway, which mostly runs northwest–southeast, heads northeast from Newport News, serving as one highway connecting the downtown areas of Newport News and Hampton.  SR 143 parallels both US 60 and Interstate 64 (I-64) extensively, and sometimes very closely, throughout its course.  The state highway also runs concurrently with US 60 in Hampton and with US 17 in Newport News. Falls Church is an independent city in the U.S. state of Virginia.  As of the 2010 census, the population was 12,332.  The estimated population in 2015 was 13,892.  Falls Church is included in the Washington metropolitan area.  Falls Church has the lowest level of poverty of any independent city or county in the United States. WBTJ is a Mainstream Urban formatted broadcast radio station licensed to Richmond, Virginia, serving the Richmond/Petersburg area.  WBTJ is owned and operated by iHeartCommunications, Inc. In the United States, an independent city is a city that is not in the territory of any county or counties with exceptions noted below.  Of the 41 independent U.S. cities, 38 are in Virginia, whose state constitution makes them a special case.  The three independent cities outside Virginia are Baltimore, Maryland; St. Louis, Missouri; and Carson City, Nevada.  The U.S. Census Bureau uses counties as its base unit for presentation of statistical information, and treats independent cities as county equivalents for those purposes.  Baltimore, Maryland is the most populous independent city in the United States. State Route 312 (SR 312) is a primary state highway in the U.S. state of Virginia.  Known as J. Clyde Morris Boulevard and the Avenue of the Arts, the state highway runs 1.11 mi from U.S. Route 60 (US 60) east to US 17 and SR 143 within the independent city of Newport News.  SR 312 serves as a connector between US 60 and US 17 and SR 143 in the central part of Newport News.  In conjunction with US 17, the state highway connects Interstate 64 (I-64) with several cultural institutions, including Christopher Newport University. State Route 123 (SR 123) is a primary state highway in the U.S. state of Virginia.  The state highway runs 29.27 mi from U.S. Route 1 (US 1) in Woodbridge north to the Chain Bridge across the Potomac River into Washington from Arlington.  It goes by three local names.  From its southern terminus to the Occoquan River Bridge, it is known as Gordon Boulevard.  From the Occoquan River Bridge to the city of Fairfax it is known as Ox Road.  North from Fairfax, it is known as Chain Bridge Road.  SR 123 is a partial circumferential highway in Northern Virginia that connects Woodbridge in eastern Prince William County with the independent city of Fairfax and the Fairfax County communities of Vienna, Tysons Corner, and McLean, the last the home of the National Counterterrorism Center and the Central Intelligence Agency.  The state highway also connects all of the major highways that radiate from Washington, including Interstate 95, I-66, US 29, US 50, SR 267, and the George Washington Memorial Parkway.  Furthermore, SR 123 crosses another pair of circumferential highways, I-495 and the Fairfax County Parkway, and SR 7, a major northwest–southeast highway through Northern Virginia.  The state highway is a part of the National Highway System for its entire length. The National Historic Landmarks (NHLs) in the U.S. state of Missouri represent Missouri's history from the Lewis and Clark Expedition, through the American Civil War, the Civil Rights Movement, and the Space Age.  There are 37 National Historic Landmarks in Missouri.  One site in Missouri was once a National Historic Landmark but later had its designation withdrawn when it failed to meet the program's criteria for inclusion.  The NHLs are distributed across fifteen of Missouri's 114 counties and one independent city, with a concentration of fifteen landmarks in the state's only independent city, St. Louis. Petersburg is an independent city in the U.S. state of Virginia.  As of the 2010 census, the population was 32,420.  The Bureau of Economic Analysis combines Petersburg (along with the city of Colonial Heights) with Dinwiddie County for statistical purposes.  It is located on the Appomattox River and 21 mi south of the state capital of Richmond.  The city's unique industrial past and its location as a transportation hub combined to create wealth for Virginia and the region.
Answer: Petersburg