Harold Purchased 400 Pairs of Gloves from Isaac at a Contract

Harold purchased 400 pairs of gloves from Isaac at a contract price of $800. Fifty of the gloves were defective and a dispute arose as to the amount due and owing under the contract. Harold refuses to pay the $800, and Isaac is threatening to sue. Which of the following is correct with regard to this transaction?

A) If Isaac agrees to accept $600 to settle the dispute and Harold agrees to pay that amount, the agreement is enforceable.
B) If Isaac agrees to accept $600 to settle the dispute and Harold pays that amount, Isaac can still sue for the balance of $200 and will win the lawsuit.
C) Harold is under a pre-existing legal obligation to pay the $800.
D) Two of these but not all three