zip code tabulation area, or (II) if there is no rent described in subclause (I) for such area, the fair market rent determined by such Secretary for units with the same number of bedrooms in the same county. (ii) State option A State may in its rental reduction allocation plan provide that the market rent standard for all (or any part) of a zip code tabulation area or county within the State shall be equal to a percentage (not less than 75 nor more than 125) of the amount determined under clause (i) (after application of clause (iii)) for such area or county. (iii) Minimum amount Notwithstanding clause (i), the market rent standard with respect to any eligible unit for any year in the credit period after the first year in the credit period for such unit shall not be less than the market rent standard determined for such first year. (3) Family rental payment requirements (A) In general Each qualified rental reduction agreement with respect to any qualified building shall require that the family rental payment for an eligible unit within such building for any month shall be equal to the lesser of— (i) 30 percent of the monthly family income of the residents of the unit (as determined under subsection (e)(5)), or (ii) the applicable rent for such unit. (B) Utility costs Any utility allowance (determined by the Secretary in the same manner as under section 42(g)(2)(B)(ii)) paid by residents of an eligible unit shall be taken into account as rent in determining the family rental payment for such unit for purposes of this paragraph. (c) Rental reduction credit amount For purposes of this section— (1) Determination of amount (A) In general The term rental reduction credit amount means, with respect to any qualified building, the dollar amount which is allocated to such building (and to eligible units within such building) under this subsection. Such dollar amount shall be allocated to months in the credit period with respect to such building (and such units) on the basis of the estimates described in paragraph (2)(B).