This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
In the flowchart shown below regarding pathophysiology of polycystic ovarian syndrome, A is 
Select and explain. 
A. Inhibin - B, B. Oestrogen, C. Progesterone, D. Androstenedione
B: Oestrogen
Answer: B: Oestrogen 
Explanation: Elevated Estrone causes endometrial hyperplasia.