Hi kanigmat011,
Usage of who and whom can confuse best of grammarians...
But best way to answer - when to use 'who' and 'whom' is to put it like this....
Use 'who' when you address the nominative Case
Use 'whom' when you address the objective case
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The nominative case (abbreviated NOM) is one of the grammatical cases of a noun or other part of speech, which generally marks the subject of a verb or the predicate noun or predicate adjective, as opposed to its object or other verb arguments.
The objective case is used for nouns and pronouns which function as objects.
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For example:
______ do you talk to? I talk to Ram----> here Ram is an objective case
So answer will be : Whom do you talk to?
_____ will play the match? Ram will play the match ----> here Ram is a Nominative case
So answer will be: Who will play the match?
I hope it helped.
Now apply the same to the question....
It will be very easy to pick option C.