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
In ETC cmplex-4 is inhibited by all except ? 
Select and explain. 
A. CO, B. CN, C. H2S, D. BAL
D: BAL
Answer: D: BAL 
Explanation: Ans. is 'd' i.e.,BAL Complex I :- Barbiturates (amobarbital), piercidin A, rotenone, chlorpromazine, guanithidine.