What is special about Pseudomonas agar plates?

a) Pseudomonas agar plates are selective for gram-negative bacteria.
b) Pseudomonas agar plates contain antibiotics to inhibit the growth of gram-positive bacteria.
c) Pseudomonas agar plates contain indicators that change color in the presence of Pseudomonas species.
d) Pseudomonas agar plates are differential, allowing for the identification of Pseudomonas species based on their ability to produce specific pigments.