Burns Offers Realtor a Commission of 10 Percent of the Sales

Multiple Choice

Burns offers Realtor a commission of 10 percent of the sales price if Realtor can find a buyer for the Burns Building for $500,000. Realtor spends funds to research and obtain potential-buyer contact information and locates Walters, who is willing to accept the $500,000 offer to sell from Burns. Before any transaction takes place, Burns revokes his offer to Realtor and refuses to sell the property to Walters. Burns's revocation is:

A) valid.
B) not effective.
C) enforceable.
D) effective.