Ans. is 'c' i.e.. Estradiol f Ref: Principles of medical physiology p. 216]o Estradial, estrone and estrial, all three are found in blood, but estradiol is the most potent estrogen.o Major estrogen in normal adult women - Estradiolo Major estrogen in postmenoapusal women - Estroneo Major estrogen in pregnant women - Estriol.o In post menopausal women estrogen is formed in peripheral tissues most commonly in adipose tissue, liver kidney and brain.