under clause (i), the taxpayer shall certify to the housing credit agency the full extent of all Federal, State, and local subsidies which apply (or which the taxpayer expects to apply) with respect to the building. (m) Regulations The Secretary shall prescribe such regulations as may be necessary or appropriate to carry out the purposes of this section, including regulations— (1) dealing with— (A) projects which include more than 1 building or only a portion of a building, (B) buildings which are placed in service in portions, (2) providing for the application of this section to short taxable years, (3) preventing the avoidance of the rules of this section, and (4) providing the opportunity for housing credit agencies to correct administrative errors and omissions with respect to allocations and record keeping within a reasonable period after their discovery, taking into account the availability of regulations and other administrative guidance from the Secretary. . (b) Treatment as part of general business credit Section 38(b) of the Internal Revenue Code of 1986 is amended by striking plus at the end of paragraph (31), by striking the period at the end of paragraph (32) and inserting , plus , and by adding at the end the following new paragraph: (33) the middle-income housing credit determined under section 42A(a). . (c) Unused allocations carried over to low-Income housing credit (1) In general Clause (i) of section 42(h)(3)(C) of the Internal Revenue Code of 1986 is amended— (A) by striking the unused and inserting the sum of— (I) the unused , (B) by inserting plus after calendar year, , and (C) by adding at the end the following new subclause: (II) the unused middle-income State housing credit (if any) of such State for the preceding calendar year, . (2) Unused middle-income State housing credit The second sentence of section 42(h)(3)(C) of such Code is amended by inserting , and the unused middle-income State housing credit for any calendar year is the excess (if any) of the amount described in section