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
Pyocyanin is formed by: 
Select and explain. 
A. Yersinia, B. Pseudomonas, C. Burkholderia, D. Pasteurella
B: Pseudomonas
Answer: B: Pseudomonas 
Explanation: Ans. is. 'b' i. e., Pseudomonas