Register renaming is done to eliminate WAR (Write after Read) and WAW (Write after Write) dependency between instructions which could have caused pipieline stalls. Hence (C) is the answer.
I1: Read A to B
I2: Write C to A
Here, there is a WAR dependency and pipeline would need stalls. In order to avoid it register renaming is done and
Write C to A
Write C to A'
WAR dependency is actually called anti-dependency and there is no real dependency except the fact that both uses same memory location. Register renaming can avoid this. Similarly WAW also.