continues to be rent-restricted. (ii) Next available unit must be rented to middle-income tenant if income rises above 140 percent of income limit If the income of the occupants of the unit increases above 140 percent of the income limitation applicable under paragraph (1), clause (i) shall cease to apply to such unit if any residential rental unit in the building (of a size comparable to, or smaller than, such unit) is occupied by a new resident whose income exceeds such income limitation. (3) Date for meeting requirements (A) In general Except as otherwise provided in this paragraph, a building shall be treated as a qualified middle-income building only if the project (of which such building is a part) meets the requirements of paragraph (1) not later than the close of the 1st year of the credit period for such building. (B) Buildings which rely on later buildings for qualification (i) In general In determining whether a building (hereinafter in this subparagraph referred to as the prior building ) is a qualified middle-income building, the taxpayer may take into account 1 or more additional buildings placed in service during the 12-month period described in subparagraph (A) with respect to the prior building only if the taxpayer elects to apply clause (ii) with respect to each additional building taken into account. (ii) Treatment of elected buildings In the case of a building which the taxpayer elects to take into account under clause (i), the period under subparagraph (A) for such building shall end at the close of the 12-month period applicable to the prior building. (iii) Date prior building is treated as placed in service For purposes of determining the credit period for the prior building, the prior building shall be treated for purposes of this section as placed in service on the most recent date any additional building elected by the taxpayer (with respect to such prior building) was placed in service. (C) Special rule A building— (i) other than the 1st building placed in service as part of a project,