(a) General. — On or before the fifteenth day of the fourth month following the close of a taxable year, an income tax return under this article shall be made and filed by or for:

1. (1) Every resident individual required to file a federal income tax return for the taxable year, or having West Virginia adjusted gross income for the taxable year, determined under section twelve of this article §11-21-12 of this code in excess of the sum of his or her West Virginia personal exemptions: Provided, That the Tax Commissioner shall by legislative rule specify circumstances when an individual is not required to file a return as a result of the application of section ten of this article §11-21-10 of this code;
2. (2) Every resident estate or trust (except non-grantor trusts administered by licensed private trust companies created pursuant to the provisions of §31I-1-1 et seq. of this code) required to file a federal income tax return for the taxable year, or having any West Virginia taxable income for the taxable year, determined under section eighteen of this article §11-21-18 of this code;
3. (3) Every nonresident individual having any West Virginia adjusted gross income for the taxable year, determined under section thirty-two of this article §11-21-32 of this code, in excess of the sum of his or her West Virginia personal exemptions, except when all of such nonresident individual's West Virginia source income is taxed on a composite return filed under this article for the taxable year; and
4. (4) Every nonresident estate or trust having items of income or gain derived from West Virginia sources, determined in accordance with the applicable rules of section thirty-two of this article §11-21-32 of this code as in the case of a nonresident individual, in excess of its West Virginia exemption.

(b) Husband and wife. —

1. (1) If the federal income tax liability of husband or wife is determined on a separate federal income tax return, their West Virginia income tax liabilities and returns shall be separate.

2. (2) If the federal income tax liabilities of husband and wife other than a husband and wife described in subdivision (3) of this subsection are determined on a joint federal return, or if neither files a federal return:

   1. (A) They shall file a joint West Virginia income tax return, and their tax liabilities shall be joint and several; or
   2. (B) They may elect to file separate West Virginia income tax returns on a single or separate form, as may be required by the Tax Commissioner, if they comply with the requirements of the Tax Commissioner in setting forth information, and in such event their tax liabilities shall be separate.
3. (3) If either husband and/or wife is a resident and the other is a nonresident, they shall file separate West Virginia income tax returns on such single or separate forms as may be required by the Tax Commissioner, and in such event their tax liabilities shall be separate.