Which of the following signs would indicate cardiac arrest?

Unresponsiveness is a critical sign indicating cardiac arrest. When a person is unresponsive, it means they do not respond to stimuli, such as verbal cues or physical touch, which often indicates a loss of consciousness and is typically associated with the cessation of effective heart function and breathing. In cases of cardiac arrest, the heart stops pumping blood effectively to the brain and other vital organs, leading to a state of unresponsiveness.

While feeling faint, chest pain, and normal breathing can be concerning symptoms, they do not alone indicate cardiac arrest. Feeling faint and chest pain might signal other medical emergencies or warning signs but are not definitive indicators of cardiac arrest. Breathing normally suggests that the person is still alive and that the heart is functioning, which would rule out cardiac arrest. Thus, recognizing unresponsiveness is essential in identifying a cardiac arrest situation and responding appropriately by initiating CPR and calling for emergency help.