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: Microbiology
Shiga toxin acts by ? 
Select and explain. 
A. Activating adenylyl cyclase to increase cAMP, B. Activating guanylyl cyclase to increase cGMP, C. Inhibiting protein synthesis, D. Inhibiting DNA replication
C: Inhibiting protein synthesis
Answer: C: Inhibiting protein synthesis 
Explanation: Ans. is 'c' i.e., Inhibiting protein synthesis