(a) General. — The West Virginia adjusted gross income of a resident individual means his or her federal adjusted gross income as defined in the laws of the United States for the taxable year with the modifications specified in this section.
(b) Modifications increasing federal adjusted gross income. — There shall be added to federal adjusted gross income, unless already included therein, the following items:
(1) Interest income on obligations of any state other than this state or of a political subdivision of any other state unless created by compact or agreement to which this state is a party;