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': 'β - blockers masks all the symptoms of hypoglycemia except \nSelect and explain. \nA. Sweating, B. Increased heart rate, C. Hypertension, D. None of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: β - blockers masks all sympathetic adrenergic symptoms, but sweating is caused because of sympathetic cholinergic activity.', 'role': 'assistant'}]