This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Skeletal System, Subject name: Radiology
Most common site of OPLL is? 
Select and explain. 
A. Cervical spine, B. Thoracic spine, C. Lumbar spine, D. Sacrum
A: Cervical spine
Answer: A: Cervical spine 
Explanation: Ans AOssified Posterior Longitudinal Ligament (OPLL) - is most commonly seen in mid cervical region where it classically causes spinal canal stenosis and cord compression.