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
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: Ans. is 'b' i.e., Cytochrome C oxidase Inhibitors of Electron transport chain (Respiratory chain)o Complex IBarbiturates (amobarbital), piercidin A. rotenone, chlorpromazine. guanithidine.o Complex IICarboxin. TTFA, malonate.o Complex IIIDimercaprol, BAL, actinomycin A, Naphthvloquinone.o Complex IV (cytochrome c oxidase) :- Carbon monoxide (CO-), cyanide (CN-), H2S. azide (N3-)