This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Physiology
Ovulation is primarily caused by preovulatory surge of 
Select and explain. 
A. Estradiol, B. Luteinizing hormone, C. Progesterone, D. Follicle stimulating hormone
B: Luteinizing hormone
Answer: B: Luteinizing hormone 
Explanation: Estrogen levels peak towards the end of the follicular phase. This causes a surge in levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). This lasts from 24 to 36 hours, and results in the rupture of the ovarian follicles, causing the oocyte to be released from the ovary the oviduct.Ref: Ganong&;s review of medical physiology; 24th edition; page no:-406