rental property (as defined in section 168(e)(2)(A)) of the taxpayer with respect to which— (i) a rental reduction credit amount has been allocated by a rental reduction credit agency of a State, and (ii) a qualified rental reduction agreement is in effect. (B) Building not disqualified by other assistance A building shall not fail to be treated as a qualified building merely because— (i) a credit was allowed under section 42 with respect to such building or there was any other Federal assistance in the construction or rehabilitation of such building, (ii) the rehabilitation credit determined under section 47 was allowed under section 38 with respect to such building, or (iii) Federal rental assistance was provided for such building during any period preceding the credit period. (b) Qualified rental reduction amount For purposes of this section— (1) In general The term qualified rental reduction amount means, with respect to any eligible unit for any month, an amount equal to the applicable percentage (as determined under subsection (e)(1)) of the excess of— (A) the applicable rent for such unit, over (B) the family rental payment required for such unit. (2) Applicable rent (A) In general The term applicable rent means, with respect to any eligible unit for any month, the lesser of— (i) the amount of rent which would be charged for a substantially similar unit with the same number of bedrooms in the same building which is not an eligible unit, or (ii) an amount equal to the market rent standard for such unit. (B) Market rent standard (i) In general The market rent standard with respect to any eligible unit is— (I) the small area fair market rent determined by the Secretary of Housing and Urban Development for units with the same number of bedrooms in the same 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