(a) Under regulations prescribed by the Franchise Tax Board, if:

(1) An individual does not file a joint return for any taxable year,

(2) That individual does not include in gross income for that taxable year an item of community income properly includable therein,

(3) The individual establishes that he or she did not know of, and had no reason to know of, that item of community income, and

(4) Taking into account all facts and circumstances, it is inequitable to include that item of community income in that individual’s gross income, then, for purposes of Part 10 (commencing with Section 17001) and this part, that item of community income shall be included in the gross income of the other spouse (and not in the gross income of the individual). Under procedures prescribed by the Franchise Tax Board, if, taking into account all the facts and circumstances, it is inequitable to hold the individual liable for any unpaid tax or any deficiency (or any portion of either) attributable to any item for which relief is not available under the preceding sentence, the Franchise Tax Board may relieve the individual of that liability.