When Mr Adams Tells the Local Boys' and Girls' Club That

When Mr. Adams tells the local Boys' and Girls' Club that he will give them $5,000 if they promise to use the funds for their summer camping program, this is an example of which one of the following?

A) Promissory estoppel
B) When accepted by the club, a unilateral contract
C) Gratuitous promise
D) Inadequate consideration
E) When accepted by the club, a bilateral contract