This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
Which pa of bacteria is most antigenic - 
Select and explain. 
A. Proetin coat, B. Lipopolysaccharide, C. Nucleic acid, D. Lipids
D: Lipids
Answer: D: Lipids 
Explanation: Antigens are usually proteins and polysaccharides, and less frequently, lipids. This includes pas (coats, capsules, cell walls, flagella, fimbrae, and toxins) of bacteria, viruses, and other microorganisms. Lipids and nucleic acids are antigenic only when combined with proteins and polysaccharides. Ref: Ananthanarayan & Panikers textbook of microbiology 9th edition pg:88