Final answer:
A minimum of four officers are recommended for a Contact team responding to an active shooter to ensure tactical advantage and safety.
Step-by-step explanation:
The minimum number of officers on a "Contact team" for an active shooter situation is typically understood to be four. This protocol has been established based on best practices in law enforcement for effectively confronting an active shooter. The goal is to maximize the safety of the officers and potential victims while providing a tactical advantage. Four officers allow for a diamond formation, which can be used to enter rooms and corridors from multiple points, thereby reducing the shooter's ability to focus on a single target. Additionally, it permits multiple angles of response, a 360-degree security envelope, and a force multiplier if engagement with the shooter occurs.