The correct option is C Hypothalamus
The hypothalamus responds to a variety of signals from the internal and external environment including body temperature, hunger, feelings of being full up after eating, blood pressure and levels of hormones in the circulation. It also responds to stress and controls our daily bodily rhythms, such as the night-time secretion of melatonin from the pineal gland and the changes in cortisol and body temperature over a 24-hour period.