What type of fungal infections does terbinafine primarily target?

Terbinafine primarily targets dermatophyte infections, which are fungal infections specifically caused by dermatophytes. These fungi infect the skin, hair, and nails, leading to common conditions such as athlete's foot, ringworm, and onychomycosis (nail fungus). Terbinafine works by inhibiting a specific enzyme in the fungal cell membrane synthesis, which is crucial for their survival and growth. This makes it particularly effective against the types of fungi that cause superficial infections.

In contrast, systemic infections and invasive fungal infections are typically more severe and often require different classes of antifungal agents that target fungi living within the body or bloodstream. Yeast infections, often caused by Candida species, also require different antifungal medications that are more effective against those specific organisms. Thus, terbinafine’s mechanism and activity profile align closely with treating dermatophyte infections, making it the correct answer for this question.