The best answer is B. Lines 16-19 of the passage state that the existence of a Pullman-owned union "weakened support among Black workers for an independent entity"
og得解释,我不太明白这句话怎么看得出pullman union 是有部分porter支持,请指教,或者给偶翻译一下,觉得这话也不难懂啊?
In the Pullman contest Randolph faced formidable obstacles. The first was Black workers’ understandable skepticism toward unions, which had historically barred Black workers from membership. An additional obstacle was the union that Pullman itself had formed, which weakened support among Black workers for an independent entity.