I cannot get confirmation that it was David Hockney, I have looked at a few of his paintings and cannot see any dogs. I know Cuneo always hid the mouse away in his paintings but surely it would be too difficult to hide a dog!
It's a bit of a silly question... but at the Norman Rockwell exhibition earlier this year I was struck by how many of his works featured a personality-full dog somewhere. So my answer would be him - or, more obviously, George Rodrigue.
The fact that it's in a quiz does not preclude it being a silly question! It clearly is a VERY silly question as there cannot possibly be one correct answer.