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
Ovary develops from all except 
Select and explain. 
A. Coelomic Epithelium, B. Yolk sac endoderm, C. Gonadal ridge mesenchyme, D. Urogenital sinus
D: Urogenital sinus
Answer: D: Urogenital sinus 
Explanation: Ovary develops from 3 major cellular sources

Primordial germ cells
Coelomic epithelial cells
Mesenchymal cells from gonadal ridge.