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
FADH2 enters the respiratory chain through which complex? 
Select and explain. 
A. I, B. II, C. III, D. IV
B: II
Answer: B: II 
Explanation: 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