Answer:
B
Step-by-step explanation:
The word "most" is the superlative, which means that it's the utmost one. In other words, you only use "most" of any other such superlative word when you say something like "her office was the most". Usually, "the" precedes a superlative. Since none of the sentences with "most" have "the", eliminate A and D.
"More" is a little different from "most" in that it is the comparative. It's like "good, better, best", and "more" is the "better" (hope this analogy makes sense). Similar to how "most" goes with "the", "more" and any other comparative often go with "other" because you're comparing two things. Since C doesn't have "other", we can eliminate it.
Thus the answer is B.
Hope this helps!