a) Own a camera?
Having a camera doesn't make one a photographer anymore than having a hammer and a chisel makes one a carpenter. Or, owning a racehorse makes one a jockey.
b) Know how to use a DSLR?
There are people who use a DSLR in the course of their work (e.g. a biologist, or an orthodontist) but do not have any interest in photography. Hence, knowing how to use a DSLR does not necessarily make one a photographer.
c) Love to take photographs?
These days, many people take photos exclusively with a smartphone. They also publish or share photos in the social media. Yet most of these people will not call themselves a photographer.
d) Have ability to do post editing?
Strictly speaking, post editing cannot be used to determine if one is a photographer or not. It wasn't so long ago that people were still using film and the darkroom and photoshop was unheard of. We cannot disqualify all the photographers of yore just because they did not do any post editing on a computer!
e) Have extensive knowledge of cameras and lenses?
If that makes you a photographer, then why are photography schools not spending more time training their students on cameras and lenses?
f) Have lots of photography equipment?
Does having a garage full of tools make you a carpenter or a mechanic?
So, who is a photographer?
Now that I have listed down what does not make one a photographer, I am obliged to offer my view of what makes one a photographer. A photographer is one who strives to master the art or the craft of photography, depending on whether he defines for himself that it is an art or it is a craft. It is a continuous quest and it never ends. You are a photographer when you start to call yourself one and seriously begin on a continuous journey to master the art (or craft).