Final answer:
The first stage of an emotional response after a traumatic event is the alarm reaction, where the body experiences immediate physiological reactions to prepare for a threatening situation. It is analogous to the fight-or-flight response.
Step-by-step explanation:
After a traumatic event, the first stage of the emotional response is the alarm reaction. This is when the body's immediate physiological reaction to a threatening situation or emergency occurs. It is analogous to the fight-or-flight response, where the body prepares to either confront the threat or escape from it. During the alarm reaction, the body experiences a cascade of physiological reactions that provide energy to manage the situation.