The correct answer is:
A. It sends an electric shock to the heart.
An Automated External Defibrillator (AED) is a device designed to analyze the heart's rhythm and determine if a shock is needed to treat a life-threatening cardiac arrhythmia, such as ventricular fibrillation or pulseless ventricular tachycardia. If a shock is advised, the AED delivers an electric shock to help restore a normal heart rhythm.