With Regard Only to the Requirement of Consideration,which One of the Following

Multiple Choice

With regard only to the requirement of consideration,which one of the following would be a binding contract?

A) a promise by Tom to drive a co-worker to Timmins
B) a promise to give $10 exchanged for a promise to give a can of pop
C) a promise by Mr. Brent to pay $25 to John who found and returned Brent's wallet, which Brent didn't even know he had lost until John delivered it
D) an agreement between a contractor and a homeowner that the owner would pay an additional $1000 if the contractor would complete the existing contract according to all its terms
E) a written promise, but not under seal, to give John $50 on Saturday