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: Forensic Medicine
A doctor has to do an urgent operation on an unconscious patient to save his life. But there are no relatives to take consent. He goes ahead without obtaining consent from anyone; he is using the principle of: CMC (Vellore) 09 
Select and explain. 
A. Therapeutic privilege, B. Doctrine of implied consent, C. Therapeutic waiver, D. Doctrine of informed consent
B: Doctrine of implied consent
Answer: B: Doctrine of implied consent 
Explanation: Ans. Doctrine of implied consent