Friends can
a. you learn about yourself and how to get along with others
b. show you a different aspect of the world
c. give you a sense of belonging and a safe place to talk
d. all of the above

D. all above

Having a friend is all about having someone there for you (and being there for someone) and cooperating with another person. So A and C are correct, as well often your friends have different experiences, so B is correct.