This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: ETC, Subject name: Biochemistry
[{'content': 'MELAS inhibit all ETC Complexes EXCEPT: \nSelect and explain. \nA. I, B. II, C. III, D. IV', 'role': 'user'}, {'content': 'Answer: B \nExplanation: MELAS (mitochondrial encephalopathy, lactic acidosis, and stroke) MELAS inhibits complex I, III & IV of ETC. It is an inherited condition due to NADH-Q oxidoreductase, Caused by a mutation in mitochondrial DNA Involved in Alzheimer disease and diabetes mellitus. ETC is affected, brain is affected and due to anaerobic metabolism, lactic acidosis occurs.', 'role': 'assistant'}]