Which of the following is the best example of positive peer pressure?

a. your friend says "no " to the dinner your dad cooked and prefers to just hang out with friends instead.

b. your teammates keep making fun of you for spending so much time studying for friday's math test.

c. your coworkers spend every weekend watching movies at tim's house and invite you to join them.

d. your friends all sign up for a free class at the gym and suggest you sign up for it, too.