Kim just started dating Martin. Kim's best friend Sandy is mad because Sandy is alone and she wishes she had a boyfriend. She has decided to not talk to Kim for a while. Which rule of friendship is Sandy breaking?

A) Don't be jealous. B) Stand up for your friend. C) Seek to repay debts and compliments. D) Volunteer in time of need.

Answer: A) Don't be jealous

Explanation:

According to the question, Sandy is mad at Kim because she has started dating a boy and now has a boyfriend but Sandy does not have boyfriend. Thus, Sandy has stopped talking to Kim as she is feeling jealous of her friend. Thus, she is breaking rule of not being jealous of your friend rather support and feel happy for him/her.

Other options are incorrect because standing up for friend, volunteering when friend is in need and oblige for giving complement and repaying favors are not the rules of friendship broken by Sandy. Thus, the correct option is option (A).