Background -
object pronoun -
1. he loves her (object of verb)
2 .he is crazy after her (object of preposition)
There is no other instance in english where an object form of pronoun is used
Current problem
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
we need "one' to be a subject of the second clause.. we need the construction where one is part of a subgroup - presenters and hence we need to use "one of" .. which need "whom" the object of preposition
if the sentence was
The Presenter one who is blind, will demonstrate adaptive equipment that allows visually impaired people to use computers.
we could have used "one who" who modifying "one"[/list]