The correct option is D All of these
Pineal body is a very small, reddish-grey, vascular, conical, solid body located in the brain. It secretes a hormone named melatonin. Melatonin concentrates pigment granules in the melanocytes, making the skin colour lighter in certain animals. It also regulates the functioning of gonads, thus, controls, sexual behaviour and regulates the period of puberty.