Betty and Barney file a joint federal income tax return. They may file separate Maryland income tax returns if which of the following apply?

Barney and Betty maintain their principal place of abode in the same Maryland county on December 31st of the current year.

Barney is a Maryland resident and Betty is a Virginia resident and therefore a nonresident of Maryland.

Barney and Betty are both Maryland residents, but Barney only works in Virginia and not in Maryland.

Barney and Betty both live in Maryland and are residents but both work only in Virginia