This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vitreous and retina, Subject name: Ophthalmology
All of the following take pa in the pathogenesis of macular edema in diabetic retinopathy except - 
Select and explain. 
A. Retinal pigment epithelium dysfunction, B. Oxidative stress, C. VEGF, D. Increased protein kinase-C
A: Retinal pigment epithelium dysfunction
Answer: A: Retinal pigment epithelium dysfunction 
Explanation: In diabetic Retinopathy, the pathogenesis of macular edema undeegoes: Oxidation VEGF Increased protein kinase C Ref khurana 6/e p 279