**Core Concept**
Pseudomonas species, particularly Pseudomonas aeruginosa, are opportunistic pathogens that can cause a range of infections. To isolate and cultivate these bacteria, selective media are used to inhibit the growth of other microorganisms while allowing Pseudomonas to grow.

**Why the Correct Answer is Right**
The correct answer is based on the ability of Pseudomonas to produce pyocyanin, a blue-green pigment that is toxic to many other bacteria. Selective media, such as Pseudomonas Agar Base (PAB), contain cetrimide, which inhibits the growth of most bacteria while allowing Pseudomonas to grow. This is due to the ability of Pseudomonas to produce pyocyanin, which is not affected by cetrimide.

**Why Each Wrong Option is Incorrect**
* **Option A:** MacConkey agar is a selective media for gram-negative bacteria, but it is not specific for Pseudomonas. It contains bile salts and crystal violet, which inhibit the growth of gram-positive bacteria and many gram-negative bacteria, but not Pseudomonas.
* **Option B:** Blood agar is a general-purpose culture medium that supports the growth of many bacteria, including Pseudomonas. However, it is not selective for Pseudomonas and can support the growth of other bacteria as well.
* **Option C:** Mannitol salt agar is a selective media for Staphylococcus aureus, which grows in the presence of high salt concentrations. Pseudomonas aeruginosa is unable to grow on this medium due to its inability to tolerate high salt concentrations.

**Clinical Pearl / High-Yield Fact**
Pseudomonas aeruginosa is an opportunistic pathogen that can cause a range of infections, particularly in immunocompromised patients. It is often associated with cystic fibrosis, burn wounds, and urinary tract infections.

**Correct Answer: C. Pseudomonas Agar Base (PAB)**