Hi. This quiz uses population numbers from the 2010 census, where Columbia and Memphis were the largest cities of their respective states. I haven't gotten around to updating all my quizzes with the 2020 census data. Sorry for being so slow, I'll get around to fixing this eventually.
Columbia was larger that Charleston (129K as opposed to 120K), and Memphis was larger than Nashville (647K versus 601K) as of 2010. You are correct that Charleston and Nashville have since grown larger than Columbia and Memphis, but this happened during the last decade. As you can see in the notes at the top, this quiz lists the largest cities "as of the 2010 Census".
Columbia was larger that Charleston (129K as opposed to 120K), and Memphis was larger than Nashville (647K versus 601K) as of 2010. You are correct that Charleston and Nashville have since grown larger than Columbia and Memphis, but this happened during the last decade. As you can see in the notes at the top, this quiz lists the largest cities "as of the 2010 Census".