This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of carbohydrate, Subject name: Biochemistry
One of the following molecules acts as a mobile electron carrier in the respiratory chain 
Select and explain. 
A. Ubiquinone, B. FADH2, C. FeS, D. Cytochrome b
D: Cytochrome b
Answer: D: Cytochrome b 
Explanation: Ref: Harper&;s Biochemistry; 30th edition; Chapter 13; The Respiratory Chain & Oxidative Phosphorylation