On June 15, Peters orally offered to sell a used lawn mower to Mason for $125 . Peters specified that Mason had until June 20 to accept the offer. On June 16, Peters received an offer to purchase the lawn mower for $150 from Bronson, Mason’s neighbor. Peters accepted Bronson’s offer. On June 17, Mason saw Bronson using the lawn mower and was told the mower had been sold to Bronson. Mason

immediately wrote to Peters to accept the June 15 offer. Which of the following statements is correct?

a. Mason’s acceptance would be effective when received by Peters.
b. Mason’s acceptance would be effective when mailed.
c. Peters was obligated to keep the June 15 offer open until June 20 (Law, #13, 3095).
d. Peters’s offer had been revoked and Mason’s acceptance was ineffective.

d. Peters’s offer had been revoked and Mason’s acceptance was ineffective.