A、Because he could make big money by doing this. B、Because he once was helped by a stranger on highway. C、Because people would h

One thousand forty dollars: That’s how much Thomas Weller spent to keep his gas tank full in July. (29)The serf-employed 60-year-old mechanic doesn’t have to spend his spare time on the road: but it’s a hard habit to break. Since 1966, he has patrolled the San Diego highways looking for motorists bothered by fiat tires and dead batteries. He pulls up in what was once a 1955 Ford station wagon, grabs his tools, and fixes the problem at no charge.
     It is actually a dangerous thing. But it won’t stop Weller from helping others trapped on the highway. Though his wife is quite worried about his safety, Weller thinks she is too far careful. (31) Weller was once a stranded motorist himself. Driving in Illinois when he was 16, he got stuck in a snowdrift. The man who pulled him out waved off payment, saying, "Just pass it on--Andthat’s reason why Weller is doing this. (30)His business cards don’t have his name or number on it, just this: "Assisting you has been my pleasure. I ask for no payment other than for you to pass on the favor by helping someone in distress that you may encounter."
     Once in a while, someone recognizes the "San Diego Highwayman" and his pieced-together vehicle at a gas station and insists on filling the tank, which eases the fuel costs. After all, it’ll take more than high gas prices to stop Weller.