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': 'Beneficial effects of hormone replacement therapy in early menopause \nSelect and explain. \nA. Increased Nitric oxide, B. Increased Endothelin, C. Decreased COX-2, D. Increased TNF-α', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]