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: Surgery
Tetanus is caused by - 
Select and explain. 
A. Cl. Tetani, B. Cl. Welchii, C. Cl. edematiens, D. Cl. Septicum
A: Cl. Tetani
Answer: A: Cl. Tetani 
Explanation: None