qualified residential rental project
(1) In general The term “qualified residential rental project” means any project for residential rental property if, at all times during the qualified project period, such project meets the requirements of subparagraph (A) or (B), whichever is elected by the issuer at the time of the issuance of the issue with respect to such project: (A) 20–50 test The project meets the requirements of this subparagraph if 20 percent or more of the residential units in such project are occupied by individuals whose income is 50 percent or less of area median gross income. (B) 40–60 test The project meets the requirements of this subparagraph if 40 percent or more of the residential units in such project are occupied by individuals whose income is 60 percent or less of area median gross income. For purposes of this paragraph, any property shall not be treated as failing to be residential rental property merely because part of the building in which such property is located is used for purposes other than residential rental purposes.