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: Anaesthesia
[{'content': 'A patient was admitted epidural anaesthesia with 15 ml of 1.5%. Lignocaine with adrenaline for hernia surgery. He devoled hypotension and respiratory depression within 3 minutes after administration of block. The most common cause would be: \nSelect and explain. \nA. Allergy to drug administered, B. Systemic toxicity to drug administered, C. Patient got vasovagal shock, D. Drug has entered the subarachnoid space', 'role': 'user'}, {'content': 'Answer: D \nExplanation: D i.e. Drug has entered the sub arachnoid space', 'role': 'assistant'}]