Returning for comment. I think this is a dog? I've checked this on a couple of different monitors and IMHO too much shadow detail is lost. You've got a nice catchlight in the eye, but I suspect the eye is all most voters can see on their monitors. With regard to composition, it looks like you've filled the frame and that you've composed according to rule of thirds well. Meets challenge as far as single articificial light source, but the severe loss of shadow detail is a technical deficiency that will be hard to overcome.
That very nearly counts as NO light source. Yes, my monitor is calibrated and yes, I can see the dog's face, but there just isn't enough TO look at to make it interesting. Must have been a challenge to focus in so little light. 5
I don't see any light source here, much less artificial. I think I can make out one blurry eye? In that case, I have had to score this shot extremely low for subject matter and focus being lost.