Answer:
B. Surprise
Step-by-step explanation:
I strongly believe the answer is surprise.
After reading that passage, I was surprised. This is also how any other reader will feel after reading the paragraph.
It is surprising to know that a human being can turn to a vermin over night. In fact, it raises questions. The metamorphosis of Gregor into a vermin makes a reader surprised and feel sorry for the poor man.
The answer here wouldn't have been climax because the question states that what sense of feeling does the reader after reading. Climax actually refer to the high point in a story before falling action takes place.