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
A 17-year-old girl with keratitis and severe pain in the eye came to the hospital and acanthamoeba keratitis was suspected. The patient gave the history of the following 4 points. Out of these which is not a risk factor for acanthamoeba keratitis – 
Select and explain. 
A. Extended wear contact lens, B. Exposure to dirty water, C. Corneal trauma, D. Squamous blepharitis
D: Squamous blepharitis
Answer: D: Squamous blepharitis 
Explanation: Corneal infection with acanthamoeba result from direct corneal contact with any material or water contaminated with the organism. The risk factors are : (i) Contact lens use, (ii) Trauma, (iii) Opportunistic infections.