Final answer:
Cindy's growing affection for her bus driver is an example of the b. mere exposure effect, which is the tendency to prefer familiar things, contrasting with other social psychology concepts like the reciprocity norm and bystander effect.
Step-by-step explanation:
Cindy's growing affection for the gruff and scowling old bus driver after riding the 8:30 bus to work for three months best illustrates the mere exposure effect. The mere exposure effect is a psychological phenomenon where people tend to develop a preference for things merely because they are familiar with them. This is different from the reciprocity norm, which involves feeling obligated to return a favor; mirror-image perceptions, which are mutual views often held by conflicting people; and the bystander effect, which refers to individuals being less likely to offer help to a victim when other people are present.