Answer:
C. Genres.
Explanation:
A genre is a category that a book fits into, therefore these book shelves house many genres.
Answer:
C. an informative article about the lack of community centers nationwide
Explanation: the article would be an entertaining, informative and short way of showing people the necessity of having comunnity centers and the lack of such places. Not only it would help this center in particular, but it could help others distributed around the country.
Most likely if it ends in "ing"
Answer:
When writing a restrictive clause, introduce it with the word "that" and no comma. However, if the subject is or was a human being, use "who" to introduce the clause. When talking about people in defining (restrictive) relative clauses, who is preferred to that.