This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Central Nervous system, Subject name: Pharmacology
[{'content': 'Therapeutic level of phenytoin is \nSelect and explain. \nA. 0-9 mg/ml, B. 10-19 mg/ml, C. 20-29 mg/ml, D. 30-39 mg/ml', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Phenytoin therapeutic plasma concentration is 10-20 mg/ml. Ref: K D Tripati 7th edition Page no 422. Table 30.2', 'role': 'assistant'}]