This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Muscle relaxants, Subject name: Anaesthesia
What is the time gap given in train of 4 
Select and explain. 
A. 10 Sec, B. 20 Sec, C. 40 Sec, D. None
D: None
Answer: D: None 
Explanation: In Train of four, four successive stimuli of 0.2sec are applied over 2sec,between two stimuli, the gap is 0.5sec as 4stimuli are applied at a constant interval in 2sec.