SAT句子改错题Many ancient Eastern rulers favored drinking vessels

SAT句子改错题
Many ancient Eastern rulers favored drinking vessels
made of celadon porcelain because of supposedly
revealing the presence of poison by cracking.
(A) because of supposedly revealing the presence of
poison
(B) for being supposed that it would reveal the
presence of poison
(C) because of being supposed to reveal
poison in it
(D) for it was supposed to reveal that there is poison
(E) because it was supposed to reveal the presence of
poison
可是B为什么错了啊?还有其他的选项都是哪里有问题呢?