The department shall establish two classes of priorities of developments to preserve multifamily housing. The classes, in order of descending priority, are:
(1) Class A, which includes any federally subsidized multifamily housing development at risk because the contract granting a federal subsidy with a stipulation to maintain affordability is nearing expiration or because the government-insured mortgage on the property is eligible for prepayment or near the end of its mortgage term; and
(2) Class B, which includes any other multifamily housing development with low income use or rental affordability restrictions.