This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteria, Subject name: Microbiology
The following statements are true with references to Mycoplasma except: 
Select and explain. 
A. They are the smallest prokaryotic organisms that can grow in cell free culture media, B. They are obligate intracellular organisms, C. They lack a cell wall, D. They are resistant to Beta-lactam drugs
B: They are obligate intracellular organisms
Answer: B: They are obligate intracellular organisms 
Explanation: Ans. is 'b' i.e., They are obligate intracellular organisms.(Ref: Harrison, 19th/e, p. 1163; Ananthanarayan, 9th/e, p. 386)Obligate intracellular bacteria are: M leprae, Chlamydia, Rickettsiae, Coxiella burnetti, Pathogenic treponemes so cannot grow on artificial cell free culture media. Mycoplasma grows on artificial cell free culture media.