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: Pharmacology
Blockade of neuromuscular transmission by botulinum toxin is an example of: 
Select and explain. 
A. Depolarizing blockade, B. Competitive blockade, C. Presynaptic blockade, D. Postsynaptic blockade
C: Presynaptic blockade
Answer: C: Presynaptic blockade 
Explanation: None