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: Ophthalmology
Most common cause of anterior uveitis associated with ahritis: 
Select and explain. 
A. Ankylosing spondylitis, B. Rheumatoid ahritis, C. Syphilis, D. Tuberculosis
A: Ankylosing spondylitis
Answer: A: Ankylosing spondylitis 
Explanation: Ans. Ankylosing spondylitis