og 194求助

194. Presenters at the seminar, one who is blind, will demonstrate adaptive equipment that allows visually impaired people to use computers.
(A) one who
(B) one of them who
(C) and one of them who
(D) one of whom
(E) one of which

正确答案为E。但本人不知道B错在何处。one of them who  中，them指代Presenters ，who指代one，并没有错误呀？因为n1 of n2 who/that ...的修饰对象是n1还是n2根据逻辑意思来决定，从逻辑上来讲B中who指代one，并且也is决定了指代one，符合原意。定语从句做Presenters的同位语。

迷惑，请NN帮忙！！谢谢！！

Choices B and C are ungrammatical because who competes with one as the subject of is.

不能有两个动作发出者.

what does the og's explaination mean?

who跟one都有可能做主语, 这样句子的表达就不清楚.