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
[{'content': 'Oral contraceptives act by : \nSelect and explain. \nA. Increasing LH, B. Increasing FSH, C. Decreasing LH and FSH, D. Decreasing ACTH and SRF', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Decreasing LH and FSH', 'role': 'assistant'}]