Definition: In this task, you're given a question, along with a context passage. The passage will not have a direct answer to the question, but can include some information and a clue for the answer. Assuming you can only obtain information about one entity in the passage, your job is to determine whether information from the passage can be used to answer the question. Indicate your choice as `a` for Yes or `b` for No.
Input: Question: Which of the nearby counties of the "Tennessee Valley"  has the largest population?  Passage:According to the United States Census 2013 estimate, the combined statistical area has a population of 1,313,105. It is the 42nd largest population sub-region in the United States, and the largest population region in Alabama, constituting roughly 1/4 of the state's population. It is the largest population region in Central Alabama. The northern counties of the metropolitan area overlap North Alabama known locally as the "Tennessee Valley" making it the largest metropolitan area in that region as well. Nearby counties Tuscaloosa, Etowah, and Calhoun, while not officially a part of Greater Birmingham, contribute significantly to the region's economy. The Birmingham media market covers these counties as well. Birmingham is part of the Piedmont Atlantic Megaregion containing an estimated 19 million people, while many residents also consider themselves part of the Deep South. It is classified as Southeast by the U.S. Census and also falls in the geographic area of the Upland South due to its location at the southern terminus of the Appalachian foothills. The entire MSA and CSA are within the congressional Appalachian Regional Commission's definition of Appalachia.


b