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: Pharmacology
One of the health benefits of the use of combined oral contraceptives in pre–menopausal women is that these contraceptives reduce the risk of: 
Select and explain. 
A. Deep vein thrombosis, B. Migraine, C. Ovarian cancer, D. Ischemic stroke
C: Ovarian cancer
Answer: C: Ovarian cancer 
Explanation: None