I would say the 1st one is the only one correct. The 2nd one should be who, the 3rd one should more and likely be whom, and the last one should probably be who. I don't know if I'm 100% though. I hope I helped.
Your answer is C: He wants Rohan to concentrate on the race.
Answer:
A.we know the thought of all the characters
I haven't read the book,
Apologies