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
Tumbling motility is shown by: 
Select and explain. 
A. Proteus vulgaris, B. Proteus mirabilis, C. Vibrio, D. Listeria
D: Listeria
Answer: D: Listeria 
Explanation: Listeria