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': 'FADH2 enters the respiratory chain through which complex? \nSelect and explain. \nA. I, B. II, C. III, D. IV', 'role': 'user'}, {'content': 'Answer: B \nExplanation: In Complex II (succinate-Q reductase), FADH2 is formed during the conversion of succinate to fumarate in the citric acid cycle and electrons are then passed several Fe-S centers to Q. Reference: Harper; 30th edition; Page no: 128', 'role': 'assistant'}]