**Core Concept**
Acantholysis refers to the loss of intercellular connections between keratinocytes, leading to the breakdown of epidermal integrity. This phenomenon is a hallmark of various autoimmune and inflammatory skin disorders.

**Why the Correct Answer is Right**
Pemphigus vulgaris is a chronic autoimmune disease characterized by the presence of autoantibodies against desmoglein 3, a protein crucial for cell-to-cell adhesion in the epidermis. The binding of these autoantibodies to desmoglein 3 disrupts the desmosomal connections between keratinocytes, resulting in acantholysis and the formation of intraepidermal blisters. This process ultimately leads to the detachment of skin cells, resulting in blistering and erosions.

**Why Each Wrong Option is Incorrect**
**Option A:** Psoriasis is a chronic inflammatory skin disease characterized by thickening of the epidermis and the formation of scales. While it involves an immune-mediated response, it is not primarily associated with acantholysis.

**Option B:** Lichen planus is a chronic inflammatory disease that affects the skin, mucous membranes, and nails. It is characterized by a band-like lymphocytic infiltrate and basal cell degeneration, but it does not typically involve acantholysis.

**Option C:** Erythema multiforme is an acute, self-limiting skin condition characterized by target-like lesions. It is often triggered by infections or medications, but it is not primarily associated with acantholysis.

**Clinical Pearl / High-Yield Fact**
Acantholysis is a key feature of pemphigus vulgaris, and the presence of suprabasal acantholysis is a diagnostic clue for this condition. The histopathological findings of pemphigus vulgaris can be distinguished from other blistering diseases by the characteristic "tombstone" appearance of basal cells.

**Correct Answer:** C. Pemphigus vulgaris.