llan Musky, salesman at Tesslaa Motors, will sell a car to Stue Student if Stu's dad Abner co-signs the loan. Stu whips out his cellphone, calls Abner, who tells llan he agrees to co-sign the loan. If Stu defaults on the payments, Abner's oral promise is enforceable as a contract by a. llan O b. No one because the collateral promise was not in writing. O c. The Bank O d. Tesslaa Motors