Wow! this is a real tough question. Is this question from Bradley University? Anyways, based on my research I believe that w<span>ithin the context of reinforcement and punishment, positive refers to the addition of something. If this questions refers to Operant Conditioning. </span>
Contrast is the correct answer. A character foil is a character who acts as a contrast by highlighting one of another character's qualities. I hope this will help you! Have a wonderful day!