When MrAdams Tells the Local Boys and Girls Club That He

When Mr.Adams tells the local Boys and Girls Club that he will give them $5000 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 bilateral contract
C) When accepted by the club, a unilateral contract
D) Gratuitous promise
E) Inadequate consideration