**Core Concept**
Dimorphic fungi are a group of fungi that can exist in two different forms: a yeast form and a mold form. This change in morphology is often temperature-dependent, with the yeast form typically seen at body temperature (37°C) and the mold form seen at cooler temperatures. Dimorphic fungi are an important cause of human disease, particularly in immunocompromised individuals.

**Why the Correct Answer is Right**
The correct answer is a type of fungus that does not exhibit dimorphism. Dimorphic fungi typically undergo a change in morphology in response to changes in temperature, but not all fungi exhibit this characteristic. The correct answer is a type of fungus that remains in its yeast or mold form regardless of temperature.

**Why Each Wrong Option is Incorrect**
**Option A:** *Histoplasma capsulatum* is a classic example of a dimorphic fungus, which changes from a mold to a yeast form at body temperature.
**Option B:** *Blastomyces dermatitidis* is another well-known dimorphic fungus that exhibits a change in morphology in response to temperature.
**Option C:** *Coccidioides immitis* is a dimorphic fungus that changes from a mold to a spherule form at body temperature.

**Clinical Pearl / High-Yield Fact**
Dimorphic fungi are often diagnosed using histopathology, where the yeast or mold form of the fungus is identified in tissue samples. It's essential to consider dimorphic fungi in the differential diagnosis of fungal infections, particularly in immunocompromised patients.

**Correct Answer:** D.