This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anesthesia, Subject name: Pharmacology
The plane of surgical anesthesia during ether anesthesia is defined as: 
Select and explain. 
A. Loss of consciousness, B. Loss of consciousness to the onset of spontaneous respiration, C. From onset of regular respiration to cessation of spontaneous breathing, D. Absence of reflexes
C: From onset of regular respiration to cessation of spontaneous breathing
Answer: C: From onset of regular respiration to cessation of spontaneous breathing 
Explanation: Stage of surgical anesthesia extends from onset of regular respiration to cessation of spontaneous breathing. This has been divided into four planes. Loss of consciousness to beginning of regular respiration is stage of delirium. From KD Tripati 7th edition Page no 374