Monster Your Endgame Planning Volume 1

I did a few exercises today.  Here is one needing a second opinion

Exercise 33

Barcza-Soos

Varna 1962

After 29..Nxd7(Diagram)

After 29..Ncd7

Evaluate the following plans and pick one(give full supporting analysis)

Plan A: 30.g4

Plan B: 30.Nc3 intending 31.Na4

Plan C: 30.Nc7

Grivas awards 50 points for the best plan but I do not agree with his analysis or evaluations

I solved independently and checked 30.Nxb6 Nxb6 31.Nxc5 with Bb7 in mind to exploit the queenside majority while the Kg7 is far away on the kingside. This idea was not mentioned by Grivas