Final answer:
If 'good' students are placed in remedial courses and start behaving poorly, the theory on deviance that is supported is Labeling theory.
Step-by-step explanation:
The theory on deviance that is supported if some 'good' students are placed into remedial courses and start to behave poorly and stop studying is Labeling theory (a). Labeling theory suggests that when individuals are labeled as deviant or placed in certain groups, they internalize those labels and start to behave accordingly. In this case, being placed in remedial courses may lead to students feeling stigmatized and adopting behaviors associated with being in those classes.