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: Social & Preventive Medicine
[{'content': 'Mother to hid transmission of HIV - \nSelect and explain. \nA. 25%, B. 50%, C. 605, D. 75%', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]