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: Radiology
Which of the following is not true regarding ossified posterior longitudinal ligament (OPLL)? 
Select and explain. 
A. Most commonly involves thoracic spine, B. Gradient echo MR sequence may overestimate the canal stenosis, C. MRI is best for diagnosis, D. Low signal intensity on all MR sequences
A: Most commonly involves thoracic spine
Answer: A: Most commonly involves thoracic spine 
Explanation: Ossification of the posterior longitudinal ligament most commonly involves the cervical spine and not the thoracic spine.