Big bank is a major creditor of bonwill department store. after a major loss in profits due to poor holiday sales, big bank decides to keep bonwill from bankruptcy by orally promising mary tudor, a supplier to bonwills, that it will guarantee bonwill's payment for goods that mary sells to bonwill. most likely, big bank's oral agreement: (points : 1)

a. is unenforceable under the statute of frauds.
b. is unenforceable because it is a collateral contract.
c. is enforceable under the