Except as otherwise provided in this regulation, each resident of this State shall use the same filing status: As used to file their federal income tax return; or As if the individual had been required to file a federal income tax return. An individual who is single and may be claimed as a dependent on another taxpayer's return shall use the filing status “dependent taxpayer”. A married couple who files a joint federal income tax return may file separate State income tax returns if: One spouse is a resident and the other spouse is a nonresident; The spouses are domiciled, or maintain principal places of abode, in different counties on the last day of the taxable year; The spouses have different taxable periods; or The Comptroller determines circumstances warrant.