are met with respect to property if such property has, as of the date of the sale or transfer referred to in paragraph (1), a covenant or other binding legal restriction sufficient to— (A) obligate, at all times during the 30-year period beginning on such date, each owner of such property with respect to the portion of such period during which such owner owns such property, to maintain such property as either— (i) residential rental property (within the meaning of section 168) not less than 75 percent of the units of which are affordable to low-income families and either occupied by or available for use by low-income residents, or (ii) a shelter eligible for assistance under title IV of the McKinney-Vento Homeless Assistance Act, and (B) provide any person a right to obtain injunctive relief to enforce the obligations described in subparagraph (A). (4) Notification of Department of Housing and Urban Development The requirements of this paragraph are met with respect to any property if, not later than 90 days after the date of the sale or transfer referred to in paragraph (1), the transferor notifies the Secretary of Housing and Urban Development of such transfer in such manner as such Secretary may provide. (5) Special rule with respect to period within which property must be replaced In the case of a sale or transfer described in paragraph (1), subsection (a)(2)(B)(i) shall be applied by substituting 3 years for 2 years . (6) Special rule for real property held for productive use in trade or business For purposes of subsection (a), if the real property described in paragraph (1) is held for productive use in a trade or business or for investment, property of a like kind to be held either for productive use in a trade or business or for investment shall be treated as property similar or related in service or use to the property so described. . (b) Enforcement obligations of the Department of Housing and Urban Development With respect to each property with respect to which the Secretary of Housing and Urban