It can be either 1 or 4 because in 1, when you call someone thin that can have an emotional effect on the person depending on if they like being thin or not, but in 4, calling someone scrawny is more of an insult.
So, to conclude, I suggest going with 4 just to be on the safe side but hopefully my explanation of 1 opened your mind a tad bit more. :)
P.S. You spelled which incorrectly! ;)
