Which of the Following Is Negative Reinforcement

Which of the following is negative reinforcement?

A) Emmanual is having a temper tantrum so his mother gives him a cookie and then he is quiet. In the future, mom is likely to give cookies to quiet him.
B) Crystal is spanked for fighting with her sister. She continues to fight with her sister.
C) George is grounded for breaking curfew. He gets home on time after that.
D) Terra's boyfriend cheats on her because she has been neglecting him for weeks. She breaks up with him.