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: Forensic Medicine
Cyanide poisoning acts by : 
Select and explain. 
A. Inhibiting DNA synthesis, B. Inhibiting enzymes of proteins synthesis, C. Inhibiting cellular respiration, D. Inhibiting protein breakdown
C: Inhibiting cellular respiration
Answer: C: Inhibiting cellular respiration 
Explanation: C i.e. Inhibit cellular respiration