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': 'After starting your patient on imipramine, his heart rate rises to 120/min and he has blurred vision. These effects can be explained by the fact imipramine: \nSelect and explain. \nA. Is a muscarinic antagonist, B. Potentiates epinephrine, C. Is a ganglionic blocker, D. Is a potent a-adrenergic blocker', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]