**Core Concept**
Systemic fungal infections are caused by various fungi that can affect different parts of the body. **Opportunistic fungi** take advantage of a compromised immune system to cause infection. **Pathogenic fungi** can cause disease in healthy individuals.

**Why the Correct Answer is Right**
The correct answer includes **Cryptococcus neoformans**, **Histoplasma capsulatum**, and **Paracoccidioides brasiliensis**, which are all known to cause systemic fungal infections. **Cryptococcus neoformans** infects the lungs and central nervous system, while **Histoplasma capsulatum** affects the lungs and can disseminate to other organs.

**Why Each Wrong Option is Incorrect**
**Option D:** **Naegleria fowlerie** is an amoeba that causes primary amebic meningoencephalitis, not a systemic fungal infection.
**Option E:** **Isospora belli** is a protozoan that causes intestinal infection, not a systemic fungal infection.

**Clinical Pearl / High-Yield Fact**
Systemic fungal infections often occur in immunocompromised patients, and prompt diagnosis and treatment are crucial to prevent serious complications.

**Correct Answer:** A, B, C. Cryptococcus neoformans, Histoplasma capsulatum, Paracoccidioides brasiliensis.