Final answer:
The bully has most clearly displayed aggressive behavior towards Allan by physically assaulting him and taking his lunch.
Step-by-step explanation:
The bully has most clearly displayed aggressive behavior, as defined by your textbook. Bullying is repeated negative treatment of another person, often an adolescent, over time, and it can include physical or verbal attacks. In this case, the bully physically assaulted Allan by shoving him to the ground, kicking him, and taking his lunch.