Question

Which sentence uses adjectives and adverbs​ correctly?  

Answer 1

I think the answer is D but I am not 100%

Answer 2

The correct answer is B. A customer who has fewer than ten items may use the express line.  
A is incorrect because it should be "I can barely hear," and not "I can't barely hear;" C is incorrect because it should be "fewer" credits, and not "less" given that credits is a countable noun; D is incorrect because it should be "She scored well on the quiz" given that you should use an adverb rather than an adjective after a verb.