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': 'A 70 year old man was administered, penicillin i.v. Within 5 minutes, he developed generalized urticaria, swelling of lips, hypotension and bronchospasm. The first choice is to administer : \nSelect and explain. \nA. Chlorpheniramine inj, B. Epinephrine inj, C. High dose hydrocortisone tablet, D. Nebulized salbutamol', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]