CAT C is radius 2.7
CAT D is 3.6
CAT E is 4.5
With a MDA below 1000ft.
Worth pointing out that those limits only apply to old style TERPS plates. the newer ones (inverse bold C) have differing circling radii, as do pans ops plates. I think it varies with MDA/H too. Which is why i really don't like flying them operationally. Why procedures designers didn't stick with a standardized radius across al types of plate I won't know; at the bare minimum (no pun intended) Circling minima should include the circling radius you can go out to.
We use CAT E, however, has to be a heavyweight clean wing approach (no slat or flap) to require this.
I also have operationally used CAT E minima to prevent the cowboy style approach talked about above; by reverting to cat E minima, you have far more space to manoevre (as long as you have the visibility and cloudbase to do this of course)