<prompt> Which of the following is responsible for green color on antibiotic disk sensitivity testing?Pyoverdin and pyocyaninPneumolysinOptochinAlpha hemolysin  <response>: Ans. a Pyoverdin and pyocyanin. Pseudomonas produce pigments by the name of pyoverdin and pyocyanin leading to greenish pigmentation in culture plate. Pneumococci produce pneumolysin that break downs hemoglobin into a green pigment. This causes pneumococcal colonies to be surrounded by green zone during growth on blood agar plates. The plate in question is not blood agar.Image source- stylefont-family: Times New Roman, Times, serif 