With no explanation, chose the best option from "A" or "B". John and Jim shared a taxi from work to the subway station when the taxi driver turns to ask for the 20 dollar fare. John wants to respond to the taxi driver's body gesture.

A: John pulls out a twenty and tells the taxi driver that he's got the whole fare covered.
B: John pulls out a ten and gives it to the taxi driver to pay for his half of the fare.
A.