A pronoun can substitute a noun or a noun phrase. Among the options above only C. him and D. They are pronouns: stories is a noun and many could be a pronoun if is was standing alone, but here it is a part of a noun phrase.
C. him is singular, so the right answer is D. They
The first statement corresponds to a Statement of reason. The linker "because" indicates reason, so what follows is a the reason why extreme celebrity workship is a serious problem.
The second thesis statement corresponds to a cause and effect structure. This is best indicated by the verb "caused by" which introduces the causes that lead to Extreme celebrity workship, which would be the effect.
The last thesis statement corresponds to the structure problem and solution. The word 'solved' is a good indication of the structure. As a result, what follows is a solution to the problem of Extreme celebrity solution.
I would say B) Hospitality
