Which has the most positive connotation? A Chubby B plump C fat D Dumpy

I would probably say plump.

Essentially, in this question, you're looking for the word that would be the least insulting. More broadly, when asked about positive connotation, you're looking for a word that is not viewed negatively.

Words like fat and cheap have negative connotations, especially when applied to people. Words like plump and frugal are much more positive.