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
[{'content': 'All of the following take part in the pathogenesis of macular edema 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: Etiopathogenis of diabetic retinopathy (including macular edema) \n\nFollowing factors are important in development of diabetic microangiopathy, which is responsible for the development of retinopathy :-\n\n\nActivation of protein kinase C\nOxidative stress\nIncreased production of growth factors, amongst which Vascular endothelial growth factor A (VEGF-A is the most important). Other factors are TGF - β, PDGF, EGF and IGF', 'role': 'assistant'}]