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
Elek's gel precipitation test is seen in ? 
Select and explain. 
A. Clostridium, B. Corynebacterium, C. Bacteroides, D. Campylobacter
B: Corynebacterium
Answer: B: Corynebacterium 
Explanation: None