Final answer:
In case of a fire announcement, the charge nurse must prioritize patient safety. The primary action is to evacuate non-ambulatory patients immediately, according to the 'RACE' protocol in fire safety procedures.
Step-by-step explanation:
The priority action for a charge nurse on a medical unit when the announcement of a fire is made is to ensure the safety of the patients and staff by following established emergency protocols. The most appropriate response from the given options is: A) Begin evacuating non-ambulatory patients first. This is in line with the "RACE" acronym used in fire safety, which stands for Rescue, Alarm, Contain, and Extinguish/Evacuate. Evacuating non-ambulatory patients first addresses the 'Rescue' aspect, as these patients are the most vulnerable and cannot self-evacuate in case of a fire. Subsequent actions would include calling the emergency response team, but patient safety is always the foremost priority.