Nate Promises to Pay for Medical Services Provided by Otto

Multiple Choice

Nate promises to pay for medical services provided by Otto to Polly. Nate receives no personal benefit for the promise. To be enforceable, the promise must be in writing if

A) Nate promises to pay only if Polly does not pay.
B) Nate assumes primary financial responsibility for the cost.
C) Otto's services will be provided in installments with separate payments.
D) Polly also promises to pay.