This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: JIPMER 2018, Subject name: Anaesthesia
A resident at the emergency depament is preparing for a lumbar puncture in a 26 years old female with suspected subarachnoid bleeding. Although she presented with altered sensorium, CT brain was found to be normal. During LP, which structure is pierced after the spinal needle crosses interspinous ligament? 
Select and explain. 
A. Ligamentum flavum, B. Arachnoid membrane, C. Areolar tissue, D. Subarachnoid space
A: Ligamentum flavum
Answer: A: Ligamentum flavum 
Explanation: Skin | Sub cutaneous fascia | Supra/inter spinous ligament | Ligamentum flava | Dura mater | Arachnoid mater | Return of CSF