Which county in West Virginia borders both Pennsylvania and Maryland?

Preston County is the correct choice because it is located in the north-central part of West Virginia and shares its northern border with Pennsylvania and its eastern border with Maryland. This geographical positioning makes it uniquely situated to border both states.

Brooke County, although located in the northern region of West Virginia, is adjacent to Pennsylvania but does not touch Maryland. Monongalia County is primarily situated further south and borders Pennsylvania but not Maryland. Mineral County is located in the eastern part of the state, bordering Maryland but not Pennsylvania, thus highlighting why Preston County is distinct in its dual borders.