**Core Concept**
Griseofulvin is an antifungal medication, but it has a narrow spectrum and is primarily used for dermatophyte infections, such as ringworm. It works by interfering with the microtubule function in fungal cells, ultimately leading to cell death.

**Why the Correct Answer is Right**
Griseofulvin is not used for systemic fungal infections because it does not effectively cross the blood-brain barrier and is not effective against a wide range of fungal pathogens. It is also not suitable for immunocompromised patients or those with deep-seated fungal infections. In contrast, other antifungal medications like amphotericin B and fluconazole are effective against a broad spectrum of fungal pathogens and can be used for systemic infections.

**Why Each Wrong Option is Incorrect**
**Option A:** Ketoconazole is an imidazole antifungal that can be used for systemic fungal infections, especially those caused by Candida and Aspergillus species. However, its use is limited due to hepatotoxicity and other side effects.
**Option B:** Fluconazole is a triazole antifungal that is commonly used for systemic fungal infections, including those caused by Candida and Cryptococcus species. Its broad spectrum of activity and ease of administration make it a popular choice.
**Option C:** Amphotericin B is a polyene antifungal that is effective against a wide range of fungal pathogens, including those that cause systemic infections. It is often used as a first-line treatment for severe fungal infections.

**Clinical Pearl / High-Yield Fact**
When treating systemic fungal infections, it's essential to consider the patient's underlying condition, the causative pathogen, and the potential side effects of antifungal medications. A thorough understanding of antifungal pharmacology and the specific characteristics of each medication is crucial to making informed treatment decisions.

**✓ Correct Answer: D. Griseofulvin**