This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
CO acts by inhibiting which component of respiratory chain ? 
Select and explain. 
A. Cytochrome b, B. cytochrome C oxidase, C. NADH CoQ reductase, D. Oxidative phosphorylation
B: cytochrome C oxidase
Answer: B: cytochrome C oxidase 
Explanation: Inhibitors of Electron transpo chain (Respiratory chain)Complex I :- Barbiturates (amobarbital), piercidin A, rotenone, chlorpromazine, guanithidine.Complex II :- Carboxin, TTFA, malonate.Complex III :- Dimercaprol, BAL, actinomycin A, Naphthyloquinone.Complex IV (cytochrome c oxidase) :- Carbon monoxide (CO), cyanide (CN), H2S, azide (N3-)