Which adapter do I use for post mount rear...
Which adapter do I use for post mount rear frame tabs (new Turner have PM rear instead of 51mm IS)
Choose the Rear IS Frame for the size of rotor you are running. So all three will work but if you are running 160mm rotors get the 160 adapter.
Standard Avid and Shimano post mount brakes will not need an adapter for 160mm rotors. Use one of them. You should not be able to run IS mount rear calipers on this frame. There maybe an adapter - but the rotors will have to be bigger - 203mm witch most likely will not fit the frame.