Yeah I've been noticing the description '4c' more and more, recently. I always thought (though pretty useless and a really narrow way of classifying what is essentially millions of unique heads of curls, kinks, coils, etc) 4a meant visibly clumping curls and coils all the way down to coffee stirrer sized, and 4b was non-clumping kinks, essentially.

I have a mixture off all sorts- pen sized, pen-spring, coffee stirrer, and loads of the non-clumping stuff, so I just describe myself as in the 4's (though if people want a more accurate description, leaning more towards 4b). I just find it all very subjective and confusing, and this "4c" has me even more confused than ever (as apparently is whoever coined the terms 'kinky crimpy' and 'kinky ziggly')