A. We can use "will have done" to talk about what will have been achieved by a certain moment in time.
e.g. I'll have finished this project by Friday.
So, (A) is not the correct option.
B. If + simple past $\to$ would/ would be
1. If It rained, you would get wet.
2. If I spoke Italian, I would be working in Italy.
So, (B) is not the correct option.
C. If + past perfect $\to$ would have/could have/ would have been
If you had studied harder, you could have passed the exam.
So, (C) is the correct option.