This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteriology, Subject name: Anatomy
Polyribosyl ribitol phosphate PRP antigen is present in the capsule of H. influenzae 
Select and explain. 
A. Serotype a, B. Serotype b, C. Serotype c, D. Serotype d
B: Serotype b
Answer: B: Serotype b 
Explanation: Capsular polysaccharide of serotype b has PRP antigen that is also used in vaccine preparation because of it's immunogenic propey.