Grady Obtains a Business Loan from Farmers County Bank

Grady obtains a business loan from Farmers County Bank.To keep Grady in business,and thereby obtain the benefits of a deal between them,Dakota promises the bank's loan officer that she will repay the loan if Grady does not.To be enforceable,Dakota's promise

A) need not be in writing.
B) must be in writing because it benefits Grady.
C) must be in writing because the bank is not a party to the other deal.
D) must be in writing because it benefits Dakota.