This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Acute coronary syndrome, Subject name: Medicine
The ratio of chest compression to rescue breath ratio for a lone rescuer in CPR for all ages is? 
Select and explain. 
A. 30:02:00, B. 15:02, C. 3:01, D. 30:01:00
A: 30:02:00
Answer: A: 30:02:00 
Explanation: The chest compression to ventilation ratio is 30: 2 for all age groups except neonatal resuscitation where the ratio is 3:1. Even in infants and children the ratio is 30:2 For adults irrespective of number of rescuers the ratio of chest compression to ventilation ratio is 30: 2. For children if 1 rescuer is present the chest compression to ventilation ratio is 30: 2 For children if 2 or more rescuers are present the chest compression to ventilation ratio is 15:2