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
Cell wall deficient bacteria are 
Select and explain. 
A. Escherichia Coli, B. Staphylococci, C. Spirochetes, D. Mycoplasma
D: Mycoplasma
Answer: D: Mycoplasma 
Explanation: None