Answer:
C. I live in a humble apartment on the second floor of a low rent building.
Explanation:
Monumental means something that has a lot of something or has importance. Oxford Dictionary defines it as
(adjective) <em>great in importance, extent, or size</em>
A, <em>"I learned a staggering amount of information in college,"</em> describes someone learning a lot of information in college. If we replaced staggering with monumental, the meaning would still be the same. The amount of information is monumental.
B, <em>"My friend lives in a colossal mansion in the hills on the edge of town,"</em> talks of a huge mansion. The word colossal can be exchanged for monumental and the meaning of the sentence would be the same. The mansion is monumental.
These two are not the answer because we want the antonym of monumental, which is the opposite of the meaning of monumental.
This leaves C, which talks about a humble apartment of a low rent building. Nothing about that is grand, important, or monumental. It is simple and small. The opposite of monumental, which is what we're looking for.
I hope this helped :D
