Answer: The 14-year-old student and the 15-year-old student.
Step-by-step explanation:
Let us examine the information and pull out details to help us answer the question.
A 14-year-old student slams a 13-year-old classmate into a metal locker. A 15-year-old student spreads a cruel rumor about a classmate.
It appears the 13-year-old student did not do anything aggressive, while the other two were cruel. This means the answer to your question is most likely:
The 14-year-old student and the 15-year-old student.