This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Normal Menstruation, Abnormal Menstruation, Menopausal Physiology and forsight of conception, Subject name: Gynaecology & Obstetrics
The increasing order of potency of estrogens is (least potent to most potent) ? 
Select and explain. 
A. E1,E2,E3, B. E1,E3,E2, C. E3, E1, E2, D. E2, E1, E3
C: E3, E1, E2
Answer: C: E3, E1, E2 
Explanation: Estradiol (E2) is most potent, followed by Estrone (E1), and Estriol (E3) is least potent