I would say A is the right one for a N development,
N has a difference from 7 Zones ( 7 f-stops) between Zone VIII and Zone I.
One f-stop has 0,30 log.D ....0,30 * 7 = 2,10.
The B graph has a difference from 1,78 log.H this would mean 6 f-stops
0,30 log.D * 6 = 1,8.
In my opinion it show's a N+1 development, not implicitly from the result
but from the exposure.