The correct option is C.
The hypothalamus is an area of the brain which contain a number of nuclei which have varieties of functions. The hypothalamus link up the nervous system and the endocrine system through the pituitary gland in the brain. The hypothalamus is responsible for the secretion of orexin hormone, which regulates appetite, wakefulness and arousal. Hypothalamus is also responsible for monitoring the secretion of other appetite hormones.