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: Microbiology
Quellung reaction is seen in 
Select and explain. 
A. Group B streptococcus, B. Staphylococcus, C. Pneumococcus, D. Enterococcus
C: Pneumococcus
Answer: C: Pneumococcus 
Explanation: Quellung reaction is seen in Streptococcus pneumoniae Quellung reaction: a specific test of Streptococcus pneumoniae. A suspension of Streptococcus pneumoniae is mixed with a drop of type-specific antiserum and a loopful of methylene blue solution. In the presence of homologous antiserum, the capsule becomes apparently swollen, sharply delineated and refractile. Reference: Textbook of Microbiology; Anathanarayan and panicker's; 10th edition; Page no: 225