Let's say that this is c. And let's just zoom in on our function. So let's say our function is doing something like, let's say it does something like, let's see, I don't want it to be defined at c, at least just for the, it could be. You can always find a limit even where it is defined. But let's say our function looks something like that. And it can even have a little kink in it the way I drew it. So it looks something like this. It's undefined.