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 centers are involved in maintaining the circadian rhythm? 
Select and explain. 
A. Supraoptic nuclei, B. Posterolateral nuclei, C. Ventrolateral nuclei, D. Suprachiasmatic nuclei
D: Suprachiasmatic nuclei
Answer: D: Suprachiasmatic nuclei 
Explanation: The entrainment process in most cases is dependent on the suprachiasmatic nuclei (SCN) located bilaterally above the optic chiasma. Efferents from the SCN initiate neural and hormonal signals that enteain a wide variety of well known circadian rhythms including the sleep wake cycle and the secretion of the pineal hormone melatonin.