Answer:
a. Mere exposure effect
Explanation:
Mere exposure effect
It is a psychological phenomenon due to which people tends to develop some preference for particular things , simply because they seems to be similar to themselves .
Hence , this effect is sometimes also called as the familiarity principle .
And according to recent study , more often someone sees the thing or even a person , the more pleasing the thing or the person becomes .
Hence , from the question information , John shows a Mere exposure effect .