(a) If a person does not file a federal income tax return, the person shall compute Maryland taxable income in accordance with the cash or accrual accounting method that:

(1) the person uses to compute income regularly in keeping the person’s books; or

(2) the Comptroller requires to reflect clearly the person’s income.

(b) If a person does not file a federal income tax return, the person shall compute Maryland taxable income:

(1) for the calendar year; or

(2) if the person keeps adequate records for an annual fiscal year accounting period, for the fiscal year.