What should officers do when confronted with an active shooter situation?

In an active shooter situation, officers are trained to prioritize a rapid response to neutralize the threat while ensuring the safety of civilians. Engaging immediately is crucial because the faster officers can address the shooter, the more lives they can potentially save.

Evacuating civilians is also essential, as it helps to minimize the risk of harm to innocent people and allows for a safer environment for law enforcement to operate. Calling for additional units ensures that there are enough resources to handle the situation effectively, whether in terms of backup officers, medical personnel, or specialized units.

Since all these actions complement one another in managing an active shooter situation—addressing the threat, protecting civilians, and seeking additional support—selecting an option that encapsulates all these responses is necessary for a comprehensive approach to the crisis. Thus, the best course of action is to initiate all these responses, which is why the answer is all of the above.