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
About Tetanus, true are all, except: 
Select and explain. 
A. Caused by exotoxin, B. Variable incubation period, C. Active immunisation is best for prophylaxis, D. Caused by endotox
D: Caused by endotox
Answer: D: Caused by endotox 
Explanation: Caused by endotox