You could be both because most people have more than one texture. We have the same hair type, though our hair probably likes different things. Oiling my scalp with castor oil every other night & protective styles have been my best friend.
Here's an easy way to tell. If your curls are approx the size of a pencil or normal size drinking straw then it's 3c. If your curls are bigger than that..about the size of a normal size (not the giant ones) sharpie marker..then your hair is 3b.
If it has curls with both those sizes.. it's combo hair. 3b/3c. When writing some people put their dominate curls pattern first. So if you hair is mainly 3c but you have some definite 3b curls.. you could write 3c/3b if you'd prefer. 4a is like pen spring size (yes the spring you find in ink pens).