**Core Concept**
The CAMP (Christie-Atkins-Munch-Peterson) test is a method used to identify certain types of streptococci based on their hemolytic activity. It involves the combination of a test strain and a known hemolytic strain, resulting in enhanced hemolysis. This phenomenon is utilized to differentiate between various streptococcal groups.

**Why the Correct Answer is Right**
Group B streptococci (Streptococcus agalactiae) are known to exhibit the CAMP phenomenon. When Group B streptococci are streaked perpendicular to a strain of Staphylococcus aureus, which is known to produce a hemolysin, the resulting zone of hemolysis is enhanced. This is due to the production of the CAMP factor, a bacteriocin that acts synergistically with the hemolysin produced by S. aureus to cause increased hemolysis. The CAMP factor is a key virulence factor for Group B streptococci, contributing to their ability to cause disease.

**Why Each Wrong Option is Incorrect**
**Option A:** Group A streptococci (Streptococcus pyogenes) do not exhibit the CAMP phenomenon. Instead, they are identified by their ability to produce a characteristic M protein, which is not related to the CAMP reaction.
**Option C:** Group C streptococci do not typically exhibit the CAMP phenomenon. They can be identified by their ability to ferment certain sugars, such as maltose or sucrose.
**Option D:** Group D streptococci, including Enterococcus species, do not exhibit the CAMP phenomenon. They can be identified by their ability to grow in the presence of 6.5% sodium chloride.

**Clinical Pearl / High-Yield Fact**
The CAMP test is a useful diagnostic tool for identifying Group B streptococci, particularly in the context of neonatal sepsis or other invasive infections. It is essential to recognize the CAMP phenomenon in clinical settings to initiate appropriate antibiotic therapy and prevent complications.

**✓ Correct Answer: B. Group B**