Final answer:
In road rage incidents, the most commonly used weapon is usually fists. Therefore, the correct option is 4) Fists.
Step-by-step explanation:
In road rage incidents, the most commonly used weapon is usually fists. While other weapons like firearms, knives, and baseball bats can also be used, they are less common compared to physical violence. It's important to note that resorting to violence in any form is illegal and dangerous.