I have a pillow as a footrest right now, until i get something better haha. I think im gonna go to the showroom in london to try them all. Cant really decide from looking online.you’d have to try them really. As another poster said, the C does have a longer seat which can be uncomfortable for some people if their thighs are relatively short or they naturally sit right back in the chair. Though this can be mitigated somewhat with a footrest, which I think you should use anyway if you’re in a chair for long periods.
I found the B comfortable but small. Okay for 30 mins. The C however, I can sit in all day, every day and have done for about 10 years.