(B) "excessively impractical" is the best interpretation of the author's use of the phrase "vagrant fancies of an undisciplined mind" (line 27-28). This is evidenced by the context surrounding the phrase. Lines 28-31 go on to state that "To such men and women the humanities are useless because they serve no immediate and technological function for the practical survival of human society in the material world." The words "useless," and "no...function...practical" help to show the impractical sentiment conveyed by the author and identified in (B). Line 32 identifies people with these believes as "pragmatists," which further supports the focus on practicality here.
(E) is incorrect because the author is not intending to say that the humanists's interests are "logically inconsistent," which implies that they are untrue or flawed. The last sentence of the third paragraph states that the areas of mortality, religion, and arts that the humanists explore should have a "secondary importance" in people's lives. If these interests were logically flawed, then they would not be suggested to have any level of importance in people's lives, so (E) is incorrect.
Does this help? Let us know if you have additional questions!