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: Pathology
The most common cause of TMJ ankylosis is: 
Select and explain. 
A. Trauma, B. Osteoarthritis, C. Childhood illness, D. Rheumatoid arthritis
A: Trauma
Answer: A: Trauma 
Explanation: None