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': 'The most common route of administration of insulin is: \nSelect and explain. \nA. Intradermal, B. Subcutaneous, C. Intramuscular, D. Intravenous', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]