Answer:
c. mere exposure learning
Step-by-step explanation:
In psychology, the term mere exposure learning refers to the phenomenon by which people tend to develop a preference by some things just because they are used to them (in other words they are constantly exposed to them). By being exposed to them, people also tend to be better at establishing differences between them
In this example people are better at distinguishing individuals belonging to racial groups that they frequently encounter than individuals belonging to racial groups with whom they don't interact. We can see that these people are exposed to some racial groups (they are constantly exposed to them) and therefore they start noticing the differences among this group since they are exposed to it constantly. Thus, this is an example of mere exposure learning.