Answer:
The answer is: letter A, Observing the interactions of those in love.
Explanation:
"Sheer joy" refers to being very happy. For a monster to have "sheer joy," <em>he should observe or experience something that he hasn't encounter before.</em>
So, among the choices above, letter A<u> (Observing the interactions of those in love)</u> is something that the monster will feel very happy to see. This is because, he cannot feel such kind of situation because he is a monster. Many times, people are afraid of him, thus watching people interacting when they're in love would bring sheer joy to the monster.
Thus, this explains the answer.
