Assistance may be made under this subchapter only if the grantee certifies that it is following—

(1) a consolidated plan which has been approved by the Secretary in accordance with section 12705 of this title (referred to in such section as a “comprehensive housing affordability strategy”), or

(2) a comprehensive homeless assistance plan which was approved by the Secretary during the 180-day period beginning on November 28, 1990, or during such longer period as may be prescribed by the Secretary in any case for good cause.