With the rules remaining that have not been substituted, we still have N before T before O.
__ __ __ __ __ __ 1 2 3 4 5 6
This is our setup, and when placing O in 4, according to answer choice D. We still have to fit in N before T, both before O, between 1-3.
__ __ __ O __ __ 1 2 3 4 5 6
If K and R are going to be consecutive. There is only one space from 1-3 available now, since N and T take up two of them. This puts K and R firmly in 5 and 6 with the ability to trade off. On the other hand, F is relegated back to 1-3 as well. This fully restores our game.
I hope this helps. Please let me know if you have any other questions or would like me to elaborate further.