This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory Chain, Subject name: Biochemistry
[{'content': 'Which complex in mitochondrial ETC does not pump out H ions - \nSelect and explain. \nA. Complex I, B. Complex II, C. Complex III, D. Complex IV', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Complex II", 'role': 'assistant'}]