This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Retina, Subject name: Ophthalmology
[{'content': 'All of the following take part in the pathogenesis of macularedema in diabetic retinopathy except \nSelect and explain. \nA. Retinal pigment epithelium dysfunction, B. Oxidative stress, C. VEGF, D. Increased protein kinase - C', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. (a) Retinal pigment epithelium dysfunctionRef: Harrision 17/e, p. 2286-2287; Yanoff and Duker 2/e, p. 877- 880; Parson's 20/e, p. 294 - 298Pathogenesis of macular edema is due to the same changes as overall for DR.", 'role': 'assistant'}]