; (B) provide for the stringency of such regulation to decrease as such recovery goals are met; and (C) provide for State management within such State, if such State is willing to take on such management, beginning on the date on which the Secretary determines all such recovery goals are met and, if such recovery goals remain met, continuing until such species is removed from the list of threatened species published pursuant to subsection (c). (3) Cooperative agreement A regulation issued under paragraph (1) that prohibits an act described in section 9(a)(1) with respect to a resident species shall apply with respect to a State that has entered into a cooperative agreement with the Secretary pursuant to section 6(c) only to the extent that such regulation is adopted by such State. (4) State recovery strategy (A) In general A State may develop a recovery strategy for a threatened species or a candidate species and submit to the Secretary a petition for the Secretary to use such recovery strategy as the basis for any regulation issued under paragraph (1) with respect to such species within such State. (B) Approval or denial of petition Not later than 120 days after the date on which the Secretary receives a petition submitted under subparagraph (A), the Secretary shall— (i) approve such petition if the recovery strategy is reasonably certain to be implemented by the petitioning State and to be effective in conserving the species that is the subject of such recovery strategy