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
The electron flow in Cytochrome C oxidase can be blocked by: 
Select and explain. 
A. Rotenone, B. Antimycin-A, C. Cyanide, D. Actinomycin
C: Cyanide
Answer: C: Cyanide 
Explanation: C i.e. Cyanide