This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Regional anaesthesia, Subject name: Anaesthesia
[{'content': 'Spinal anesthesia is given at which of the following levels \nSelect and explain. \nA. L1-2, B. L2-4, C. Midline of thorax, D. Below L5', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Spinal anesthesia is usually injected at L2-L3, L3-L4', 'role': 'assistant'}]