Answer: B. His best friend, Trevor, who is always talking about how important it is to wear a seat belt, is in the car with him.
Step-by-step explanation:
The theory of planned behavior predicts behavior which people can control under specific conditions. Here, Marquel can control his decision to wear a seat belt. According to social norms, one of the factors affecting planned behavior, is his friend also wearing a seat belt.
Other factors affecting planned behavior are attitudes, intention, norms, the power he believes he needs to put on the seat belt and his actual power to do so.