Answer:
D
Step-by-step explanation:
It could be many things. It could mean a loss of freedom. It could mean anger at being where he is. It could be anything but something pleasant and positive.
He's not indifferent. He's stalking. He doesn't like it there.
He doesn't find it monotonous. If he did, he wouldn't be stalking. And he wouldn't find the cage narrow.
He is anything but satisfied. That would be far too positive.
Best answer. Suffocation.