Elton Always Wanted to Play Golf but He Lacked the Confidence

Elton always wanted to play golf but he lacked the confidence. One day, he pushes himself, pulls out his clubs, heads for the golf course, and plays a decent round. For the next few days, he makes the effort and goes out golfing several times and is satisfied with his improvement. Elton's behavior is increasing in frequency because of what Lewinsohn calls

A) attribution retraining.
B) negative reinforcement.
C) response contingent positive reinforcement.
D) vicarious reinforcement.