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: Surgery
[{'content': 'Alpha adrenergic agonists are used in combination\nwith Local anesthetics to \nSelect and explain. \nA. increase the rate of liver metabolism of local anesthetic, B. increase the concentration of L.A at receptor site, C. stimulate myocardial contraction, D. increases vascular absorption of L.A', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]