please answer both questuons

QUESTION 17 Which of the following is true of collateral contracts? The oblagor is contractually liable to the guarantor. OB . They are covered by the statute of frauds o They are considered to be original contracts. D The guarantor is primarily liable to perform his contractual duty O QUESTION 18 The equitable doctrine of allows some parties to recover under oral contracts that the statute of frauds would have ordinarily rendered enforceable. OA estoppel by representation of fact B estoppel by record proprietary estoppel D promissory estoppel