This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Systemic Bacteriology (Gram Positive Bacilli, Gram Negative Bacilli), Subject name: Microbiology
Which of the following is non-motile? 
Select and explain. 
A. C histolyticum, B. C perfringens, C. C ramosum, D. C.botulinum
B: C perfringens
Answer: B: C perfringens 
Explanation: Clostridia are Gram positive, obligate anaerobes , spore forming (bulging) bacilli. All are motile by peritrichous flagellae except Cl.perfringens and Cl.tetani type VI. Motility - 'stately' They are noncapsulated except C. perfringens and C. butyricum.