What Are the Key Elements to Ensure the Safety of All

What are the key elements to ensure the safety of all personnel participating in an emergency hospital drill? Select all that apply.

A) Use real equipment.
B) All drill communications begin and end with "This is a drill."
C) Have strict start and stop times for the drill.
D) There must be a safety officer with the sole responsibility to monitor any unsafe situations.
E) Use strategies to make the situation realistic.