Which one is not a placental hormone?
a)	HCG	b)	HCS	c)	Progesterone	d)	Melatonin

(d)

Melatonin is a naturally occurring compound found in animals, plants and microbes. In mammals melatonin is secreted by the pineal gland in the brain. It is commonly known as ‘Hormone of darkness”. It may also be produced by a variety of peripheral cells, such as bone marrow cells, lymphocytes and epithelial cells.