This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Regional Anesthesia, Subject name: Anaesthesia
[{'content': 'Arrange following structures as pierced by spinal needle during spinal block (from outside to inside) i) Interspinous ligaments ii) Ligamentum flavum iii) Supra spinous ligament iv) Epidural space \nSelect and explain. \nA. (i), (ii), (iii), (iv), B. (ii), (iv), (i), (iii), C. (iii), (i), (ii), (iv), D. (ii), (iii), (i), (iv)', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Structures as pierced by spinal needle during spinal block (from outside to inside): iii)Supra spinous ligament i) Interspinous ligaments ii) Ligamentum flavum iv) Epidural space', 'role': 'assistant'}]