The following is missing for the question to be complete:
a. mere exposure
b. proximity
c. intrinsic motivation
d. proximal incentive
Answer: A. Mere exposure
Explanation: This phenomenon studied by Robert Zajonc, also known as the principle of familiarity, is in fact a psychological phenomenon where people tend to become inclined towards certain things not because they may actually like those things, but because they are familiar with them. So was Darnell, who, while he was not passing the coffee shop, did not even know that the coffee shop existed at all and was not the object of his interest, when, due to circumstances, he began to pass by it every day and began to like that coffee shop, only because he became familiar with it.
It's actually the effect of mere exposure, what we often see or hear about something we like more. Even, according to experts, if things are known to us for completely bizarre or unbearable reasons, we will tend to like them just because they are exposed to us on a daily basis.