What gaming style? If a fast paced, first person shooter type like CSGO or LoL or Fortnite etc then I'd opt for the 9400f, it has a much better IPC than first gen Ryzen can support and there'll be less need for thread counts. If you are more online, multi-player, raid boss strategy where fps is a secondary concern and richer graphics is better then the Ryzen will be better overall as thread counts will make a sizable difference in playability.
With a Gtx960 details are going to be limited in gpu fps, either cpu will be somewhat stronger than you need graphically, but gpus change easily and no point setting limits on cpu ability before any upgrades later.
Personally, I'd go with option C, a Ryzen 3600 and live with the 2400 ram for now. The 3600 is the better of both worlds, equitable IPC to the 9400f and the thread count of the 1600. Ram is cheap compared to cpu/mobo platform and easy to upgrade later. If it even needs it.