When observing the location of these five largest cities, which of these is a common factor?
A-They are all close to an international border.
B-They are close to major bodies of water.
C-They are all located east of the Mississippi River.
D-They are all located west of the Mississippi River.

It is from USATestPrep. If you take the test then please give me the answer.

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Answer dot(3) is most used;