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: Physiology
Pacemaker regulating the rate of respiration ? 
Select and explain. 
A. Pneumotaxic centre, B. Dorsal group of nucleus, C. Apneustic centre, D. Pre-Botzinger Complex
D: Pre-Botzinger Complex
Answer: D: Pre-Botzinger Complex 
Explanation: Ans. is 'd' i.e., Pre-Botzinger Complex "The main components of the respiratory control pattern generator responsible for automatic respiration are located in the medulla. Rhythmic respiration is initiated by a small group of synaptically coupled pacemaker cells in the pre-Botzinger complex on either side of the medulla between the nucleus ambiguus and the lateral reticular nucleus".