(1) A joint return may be filed even though one of the spouses has no income or deductions. However, a joint return is not permitted if the spouses have different taxable years, if one is a resident and one is a nonresident, or either spouse is a part-year resident. A joint return must include all income and deductions of both spouses. If a joint return is filed, both the husband and the wife must sign the return, and both are jointly and severally liable for the tax.
(2) Married taxpayers who have filed a joint return may not revoke their election to file jointly and file separately unless the following conditions are met:
(a) both spouses must agree to file separately on the same form;
(b) all prior years' tax liabilities must be paid; and
(c) the tax liability determined under the joint return for the tax year for which a change is sought must be paid.