Which One of the Following Examples Is Most Likely to Be

Which one of the following examples is most likely to be the result of one or more students being trained in peer mediation?

A) At the request of his teacher, Saul makes a check mark on an index card every time Robert speaks out in class without permission.At the end of each hour, Saul tells Robert how many check marks he has made.
B) Melinda and Forrest work together on their math homework, thinking carefully about how to do each problem and then taking it one step at a time.
C) When he sees two of his classmates arguing at lunch, Abbott joins them and encourages each of them to view the conflict from the other's perspective.
D) LaVonda and Sally take turns reading excerpts from their textbook; they occasionally stop to reflect on how the new information relates to what they have previously learned.