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
Corpus luteum cyst occurs due to: 
Select and explain. 
A. HCG, B. HPL, C. Estrogen, D. Progesterone
A: HCG
Answer: A: HCG 
Explanation: Grandiose lutein cyst

Functional, non neoplastic.enlargement of the ovary.:,
Persistent corpus luteum cyst may cause local pain,
tenderness or delayed menstruation
Cysts are often palpable clinically
Usually resolve spontaneously

​Theca lutein cyst

They are associated tropphoblastic disease, chorionic gonadotrophin therapy (HCG) & clomiphene therapy.
They are bilateral and filled with straw coloured fluid.
They resolve spontaneously after elimination of the H mole, therapeutic curettage, destruction of chorio-carcinoma or discontinuation of gonadotrophin therapy.