This sentence explains that a group of speakers one of whom is quadriplegic will try to persuade the government to allow stem cell research... In the original sentence, the 'one of who' is wrong as it modifies the subject incorrectly.

Option A - incorrect
This is wrong because it uses the wrong form of pronoun in the clause. The pronoun 'who' used here is for the subject case, the right form of pronoun is 'whom' because the clause is functioning as an object.

Option B - incorrect
'Them' used here refers to the speakers and 'who' is referring to 'them' (speakers). But in the sentence, the author is saying one of the speakers, not saying someone else along with the speakers will try to persuade the government.

Option C - incorrect
The addition of the conjunction 'and' in the sentence makes it seem illogical and inappropriate. Also, 'them' is not a relative pronoun so it can't be used in relative clauses.

Option D - correct
This uses the correct form of a relative pronoun 'whom' in the clause 'one of who' to stand as the modifier of the subject 'speakers.'

Option E - incorrect
This is wrong because of the use of the relative pronoun 'which.' It is not used to refer to humans.