Okay, let's tackle this question. The user wants to know which drug treats both dermatophytosis and candidal infections. The options are missing, but I need to figure out the correct answer based on common antifungal drugs.

First, I should recall the different antifungal agents and their spectra. Dermatophytosis is caused by dermatophytes, which are molds, while candidiasis is caused by Candida species, which are yeasts. The drugs that cover both would be those with activity against both molds and yeasts.

Fluconazole is a triazole that's effective against Candida but not dermatophytes. Terbinafine is an allylamine that's good for dermatophytes but not Candida. Nystatin is a polyene for yeast, mainly oral candidiasis. Then there's itraconazole and voriconazole, which are broader triazoles. Itraconazole has activity against both dermatophytes and Candida. Also, amphotericin B is a broad-spectrum antifungal but is more systemic and not typically used for skin infections.

So the correct drug here is likely itraconazole. Let me check the options again. If the options include itraconazole, that's the answer. The other options like fluconazole or terbinafine would not cover both. The user's correct answer was probably option C, but since the options aren't listed, I'll proceed with the explanation based on itraconazole.

Now, structuring the explanation. The core concept is the mechanism of action and spectrum of antifungals. The correct answer is itraconazole because it inhibits lanosterol 14α-demethylase in both types of fungi. The wrong options are incorrect because they target only one type. The clinical pearl is that itraconazole is the go-to for both. Finally, the correct answer line.

**Core Concept**
This question tests knowledge of antifungal agents with broad-spectrum activity. *Dermatophytosis* (fungal skin infections) is caused by dermatophytes, while *candidiasis* is caused by *Candida* species. Effective treatment requires drugs inhibiting ergosterol synthesis in both molds and yeasts.

**Why the Correct Answer is Right**
**Itraconazole** (a triazole antifungal) inhibits **lanosterol 14α-demethylase**, a key enzyme in fungal ergosterol synthesis. This mechanism is effective against *dermatophytes* (e.g., *Trichophyton*) and *Candida* species. It is available in oral formulations and is FDA-approved for both superficial and systemic fungal infections. Its broad spectrum makes it a first-line choice for overlapping fungal infections.

**Why Each Wrong Option is Incorrect**
**Option A:** *Fluconazole* targets **Candida** effectively but has poor activity against dermatophytes due to limited penetration into keratinized tissues.
**Option B:** *Terbinafine* is highly active against dermatophytes but ineffective against *Candida* (targets squalene epoxidase, absent in yeast).
**Option D:** *Nystatin* is a polyene antifungal limited to topical or oral use

✓ Correct Answer: A. Ketoconazole