pursuant to paragraph (8) of this subsection in lieu of the application of such rule in section 179(d)(2)(A). (3) Qualified opportunity zone business (A) In general The term qualified opportunity zone business means a trade or business— (i) in which substantially all of the tangible property owned or leased by the taxpayer is qualified opportunity zone business property, (ii) which satisfies the requirements of paragraphs (2), (4), and (8) of section 1397C(b), and (iii) which is not described in section 144(c)(6)(B). (B) Special rule For purposes of subparagraph (A), tangible property that ceases to be a qualified opportunity zone business property shall continue to be treated as a qualified opportunity zone business property for the lesser of— (i) 5 years after the date on which such tangible property ceases to be so qualified, or (ii) the date on which such tangible property is no longer held by the qualified opportunity zone business. (e) Applicable rules (1) Treatment of investments with mixed funds In the case of any investment in a qualified opportunity fund only a portion of which consists of investments of gain to which an election under subsection (a)(1) is in effect— (A) such investment shall be treated as 2 separate investments, consisting of— (i) one investment that only includes amounts to which the election under subsection (a)(1) applies, and (ii) a separate investment consisting of other amounts, and (B) subsections (a), (b), and (c) shall only apply to the investment described in subparagraph (A)(i). (2) Related persons For purposes of this section, persons are related to each other if such persons are described in section 267(b) or 707(b)(1), determined by substituting 20 percent for 50 percent each place it occurs in such sections. (3) Decedents In the case of a decedent, amounts recognized under this section shall, if not properly includible in the gross income of the decedent, be includible in gross income as provided by section 691. (4) Regulations The Secretary shall prescribe such