Respuesta :
Answer:
I would say C. Who
Explanation:
This is because whom and which would not fit the sentence much at all. The word that is very improper in writing so try to limit the use of the word "that" in most of your writing. So the grammatically correct word would be "who".
If you have any questions feel free to ask in the comments - Mark
Also when you have the chance please mark me brainliest.