Frank is a young musician who sometimes earns extra money by playing guitar on a downtown street corner during lunch hour. He sometimes puts a dollar and a few coins in his open guitar case before he starts playing

Frank does this because he ________. a) thinks the presence of the money will encourage those who are unwilling to donate to walk away more quickly
b) feels the money in the guitar case is an incentive to encourage him to give better performances than he otherwise might
c) believes the money will increase the number of people who are attracted to the music he is playing
d) believes the presence of the money will act as a model for prosocial behavior for his audience

d