The best answer is B. The passage states that the existence of a Pullman-owned union “weakened support among Black workers for an independent entity” such as Randolp’s Brotherhood of Sleeping Car Porters. Thus, the passage suggests that some porters did support the Pullman Company union.
The passage directly contradicts A, which implies virtually no support of the Pullman company union.
Choice C is incorrect because the passage does not suggest anything about Pullman employees other than porters.
Choice D is incorrect: in fact, the passage suggests that the porters’ attitude was less positive after Randolph’s union achieved recognition in 1935.