Answer:
B. by providing social support.
Explanation:
A film director is using motivation and stress relief through humor and in that way when all people are laughing together they are becoming more motivated and friendly because they are all doing the same one thing, laughing.
This kind of action is good to use in groups or at work where there are many people and this action will motivate them to work hard and better. His worker are also going to gain confidence and respect for him.