(a)   If there is partial performance of a contract for which specified payment has been promised and the non defaulting party accepts the partial performance, they are obliged to pay fair value for the benefit they have received, but not the agreed price.

(b) If there is substantial performance of a contract for which specified payment has been promised, the non defaulting party is obliged to pay the agreed price, less an appropriate amount to compensate for the shortfall in performance.

(c)   If there is only partial performance of a contract for which specified payment has been promised, the non-defaulting party is not obliged to pay for that performance even if in fact they gain some benefit from it.