(A) is a valid argument. A society without myths will lack fundamental moral certainties, so since this society doesn’t have myths, it must lack fundamental moral certainties.

(B) is a valid argument. We know that at least one author writes both one page a day and one book per year. We know that if an author writes one page per day, they are not serious. Thus, we can logically conclude that at least one author who writes one book a year is not serious.

(C) says that all A (centers of commerce) are also B (centers of industry). It then concludes that some A are small cities, since some B are not small cities. This isn’t a valid argument — but it doesn’t have the same flaw as the stimulus.

(D) states that most of A (farmers) like B (living in rural areas), and concludes that since Carla isn’t part of A, she won’t like B. This is invalid, but doesn’t match the stimulus.

(E) says that A (sculptors) sometimes accomplish B (produce significant art), that C (musicians) are not part of A, and that thus C never accomplishes B. This is the same reasoning as in the stimulus, and has the same flaw: the author assumes that being a sculptor is the only route to producing significant art.