d is correct:in fact, the passage that the porters' attitude was less positive after Randolph's union achieved recogonition in1935.(how it come??)
Choice e is incorrrect because the passage nowwhere suggests that the general skepticism of B Black workers had no effect on their reponse to the pullman company's union.(本人认为这就是选项e的改写呀,怎么又说e错呢)