This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anaesthesia
Machine used noninvasively to monitor an external chest compression during cardiopulmonary resuscitation is 
Select and explain. 
A. Zoll depth synchronizer, B. Zoll strength sensor, C. Zoll pAO2 monitor, D. Zoll AED -plus automatic external defibrillator
D: Zoll AED -plus automatic external defibrillator
Answer: D: Zoll AED -plus automatic external defibrillator 
Explanation: None