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
[{'content': 'Route of choice for analgesics in cancer patients \nSelect and explain. \nA. Oral, B. IV, C. Topical, D. Sublingual', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]