Final answer:
The correct timeframe for a school nurse to simultaneously check for breathing and a central pulse in an unresponsive child is no more than 10 seconds. This allows for a quick decision on whether CPR or other emergency interventions are needed.
Step-by-step explanation:
When a child collapses and is unresponsive, first responders like a school nurse must perform a quick assessment to determine the next steps in emergency care. The correct timeframe to simultaneously check for breathing and a central pulse is B. No more than 10 seconds.
This rapid assessment is crucial to identify if the child requires immediate interventions such as cardiopulmonary resuscitation (CPR) or if they are in a state that suggests more advanced medical support is needed. If a pulse or normal breathing is not detected within this timeframe, the nurse should begin CPR and arrange for emergency services to be contacted immediately.