Sharon's Automobile Slid into a Ditch

Sharon's automobile slid into a ditch.A stranger pulled her out.Sharon offered to pay $25,but the stranger refused.Sharon slipped the $25 in the stranger's truck when he was not looking.

A) The $25 is a nontaxable gift received by the stranger because Sharon was not legally required to pay him.
B) The $25 is a nontaxable gift because the stranger did not ask to receive it.
C) The $25 is taxable compensation for services rendered.
D) The $25 is a nontaxable service award.
E) None of the above.