**Core Concept**
Candida albicans is a type of opportunistic yeast that commonly causes infections in humans, particularly in immunocompromised individuals. This yeast is known for its ability to form biofilms and adhere to mucosal surfaces.

**Why the Correct Answer is Right**
Candida albicans is a type of fungus that belongs to the phylum Ascomycota. It is a dimorphic fungus, meaning it can exist in both yeast and hyphal forms. The yeast form of C. albicans is the most common and is responsible for causing infections. This yeast is able to form biofilms, which are complex communities of microorganisms that adhere to surfaces and are resistant to antifungal agents.

**Why Each Wrong Option is Incorrect**
**Option A:** Aspergillus is a type of fungus that belongs to the phylum Ascomycota, but it is not a yeast. Aspergillus species are typically filamentous and cause invasive aspergillosis in immunocompromised individuals.
**Option B:** Histoplasma capsulatum is a type of fungus that belongs to the phylum Ascomycota, but it is not a yeast. H. capsulatum is typically found in soil and causes histoplasmosis in humans.
**Option C:** Cryptococcus neoformans is a type of fungus that belongs to the phylum Basidiomycota, but it is not a yeast. C. neoformans is typically found in soil and causes cryptococcosis in humans.

**Clinical Pearl / High-Yield Fact**
Candida albicans is a leading cause of nosocomial infections, particularly in intensive care units and among immunocompromised patients. It is essential to identify and treat C. albicans infections promptly to prevent complications and mortality.

**Correct Answer: C. Candida albicans**