‘Raghav read the novel in one day’ means the same as

The given sentence means that Raghav completed reading the whole novel in one day.
Only option C means exactly the given sentence. The question is given in the active voice, and option C is also in the active voice, without changing the meaning.

Option Ais a statement that on one particular day, Raghav read a single novel. 

Option B entirely overlooks the temporal perspective of a single day. 

Option D implies a habitual sentence, in the context that one day Rahul reads the novel, and the other day he does something else. 

Therefore, Option C is the correct answer.