using the same methodology and data as used for purposes of the May 2023 report of such Bureau entitled Persistent Poverty in Counties and Census Tracts ). (B) Rural county The term rural county means any county if more than 50 percent of the census blocks which comprise such county are rural blocks (as determined by the Bureau of the Census as of the date of the enactment of this Act). A rule similar to section 143(k)(2)(D) shall apply for purposes of the preceding sentence. (e) Applicable rules (1) Treatment of investments with mixed funds In the case of any investment in a qualified rural opportunity fund only a portion of which consists of investments of gain to which an election under subsection (a) 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) 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 regulations as may be necessary or appropriate to carry out the purposes of this section, including— (A) rules for the certification of qualified rural opportunity funds for the purposes of this section, (B) rules to ensure a qualified rural opportunity fund has a reasonable period of time to reinvest the return of capital from investments in qualified rural opportunity zone stock and qualified rural opportunity zone partnership interests, and to reinvest proceeds received