Why Is It Helpful for Groups to Be Comprised of Similar

Why is it helpful for groups to be comprised of similar age or developmental level children?

A) It makes scheduling groups easier because children of the same age are typically on similar schedules.
B) Different ages typically do not have similar types of victimization.
C) The groups can be facilitated at school.
D) It allows the group to be targeted to the appropriate level for teaching skills, behavior management, and so on.