date on which the Secretary publishes the final list of disqualified census tracts under paragraph (4)(B), as extended under subsection (b)(2), and (iii) the period for which any such designation is in effect shall be the period beginning on the date such designation takes effect and ending on the last day of the 10th calendar year beginning on or after the designation date as a qualified opportunity zone for the population census tract which it is replacing as such a zone by reason of the termination under paragraph (1). (D) Regulations and guidance The Secretary shall prescribe such regulations or other guidance as may be necessary or appropriate to carry out the purposes of this paragraph. (3) Disqualified census tract For purposes of this subsection— (A) In general The term disqualified census tract means any population census tract which— (i) was designated as a qualified opportunity zone before the date of the enactment of this subsection, and (ii) is described in subparagraph (B) or (C). (B) High median family income tracts (i) In general Except as provided in clauses (ii) and (iii), a population census tract is described in this subparagraph if the median family income for such tract exceeds 130 percent of the national median family income as published by Department of Housing and Urban Development or the CDFI Fund. (ii) Exception Clause (i) shall not apply if the poverty rate of such population census tract (excluding students enrolled in an institution of higher education (as defined in section 101 of the Higher Education Act of 1965)) is equal to or greater than 30 percent. (iii) Request to retain designation for certain population census tracts Clause (i) shall not apply if the Secretary, upon a request of the chief executive officer of the State made not later than 60 days after the date the Secretary publishes the list described in paragraph (4)(A), determines that— (I) the designation of such population census tract was consistent with the purposes of this subchapter, or (II) the median family