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
"Eaton" agent is: 
Select and explain. 
A. Mycoplasma, B. Pseudomonas, C. Gonococcus, D. Listeria
A: Mycoplasma
Answer: A: Mycoplasma 
Explanation: Mycoplasma