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
Gram-negative bacteria doesn't take gram stain because it is made of: 
Select and explain. 
A. Polysaccharide, B. Lipopolysaccharide, C. Techoic acid, D. None of the above
D: None of the above
Answer: D: None of the above 
Explanation: Ans. d. None of the above