(b) In any prosecution for a violation of subdivision (a) of this section, it shall be a defense that the defendant had no unpaid tax liability for any of the three consecutive taxable years.
(c) As used in this section, the terms "return" and "report" shall mean a return or report required under section one hundred ninety-two, two hundred eleven, two hundred ninety-four, fifteen hundred fifteen or fifteen hundred fifty-four of this chapter. It shall not include any return or report referred to in section one hundred ninety-seven-a, two hundred thirteen-a, or fifteen hundred thirteen of this chapter.