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
All are true about Mooren's ulcer except 
Select and explain. 
A. It is superficial ulcer, B. It spreads circumferentially, C. It is caused by infection, D. Whitish overhanging margins seen
C: It is caused by infection
Answer: C: It is caused by infection 
Explanation: Etiology of Mooren's ulcer is autoimmune not infections.