; and (2) by adding at the end the following new paragraph: (4) Individual retirement arrangements For purposes of any tax imposed by section 4973, 4974, or 4975 in connection with an individual retirement arrangement, the return referred to in this section shall be the income tax return filed by the person on whom the tax under such section is imposed for the year in which the act (or failure to act) giving rise to such liability for such tax occurred. In the case of a person who is not required to file an income tax return for the year in which the act (or failure to act) giving rise to such liability for such tax occurred— (A) the return referred to in this section shall be the income tax return that such person would have been required to file but for the fact that such person was not required to file such return, and (B) the 3-year period referred to in subsection (a) with respect to the return shall be deemed to begin on the date by which the return would have been required to be filed (excluding any extension thereof). . 5. Individual retirement arrangement defined (a) In general For purposes of this Act, the term individual retirement arrangement means an individual retirement account, an individual retirement annuity, and a Roth IRA described in sections 408(a), 408(b), and 408A, respectively, of the Internal Revenue Code of 1986. (b) Internal Revenue Code Section 408 of the Internal Revenue Code of 1986 is amended— (1) by redesignating subsection (r) as subsection (s)