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
Which of the following structure is known as the centre for 'sleep switch'? 
Select and explain. 
A. Suprachiasmatic nucleus, B. Ventro lateral preoptic area, C. Neo coex, D. Nucleus of tractus solitarius
B: Ventro lateral preoptic area
Answer: B: Ventro lateral preoptic area 
Explanation: Ventro lateral preoptic area in anterior hypothalamus plays a key role in regulation of sleep. It acts as a sleep generating nucleus thus it serves as a centre for sleep switch. Suprachiasmatic nucleus is responsible for the circadian rhythm. Ref: Ganong's Review of Medical Physiology, 23rd Edition, Page 236