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: Microbiology
[{'content': 'Which of the following exposure carries the maximum risk of transmission of HIV? \nSelect and explain. \nA. Blood transfusion, B. Sexual intercourse, C. Needle prick, D. Transplacental', 'role': 'user'}, {'content': 'Answer: A \nExplanation: HIV:\n\nMaximum risk of transmission: Blood transfusion.\nMost common route of transmission: Sexual.', 'role': 'assistant'}]