You need to attach an image of the passage so I can read it.
I guess it would either be mood or syntax
Answer:
the error is in the incorrect usage of "quick."
Explanation:
In the sample sentence, the word quick is in the verb form when it should have the -ly ending to denote that it is an adverb. That is to say, since it is describing the verb "works" it should be the adverb "quickly" instead.
B. The man who sang during half-time is Amys' dad.
It should be "The man who sang during half-time is Amy's dad."