The correct answer is option B. The degree of comparison used in the sentence is the comparative form of big which is bigger. Positive is used when we speak only of one thing. Comparative is comparing two objects. Superlative is when comparing multiple things.
It's not B. It doesn't have quotation marks. Not C because the first word in the quotations needs to be capitalized. Not D because the quotation need to surround the statement. So your answer is A :) Hope this helped :)
