I'd call that a "C" for sure. It's a Ford chassis with a built up (and out) body.
Class B's are built on a van chassis. While Class C's are built on cutaway "truck" chassis.
Small Class C's and larger Class Bs can blur the lines. There's even a Super B in between. Most, but not all Bs are built on the Mercedes/Sprinter chasis. But not all. Ford's Transit Vans are showing up in class B's as well.
Most, but not all, Class Cs are built on Ford or Chevy "cutaway" truck chassis. Most but not all have slides and or over cab bed or storage.
I looked up the Aspect that's clearly a class C built on a Ford Cutaway truck chassis - usually a F350 or F450 (or E350/E450).
2017 Winnebago Adventurer 37F
2016 Lincoln MKX Toad