**Core Concept**
Psoriasis is a chronic autoimmune skin condition characterized by rapid skin cell proliferation, leading to thickened, scaly, and inflamed skin lesions. The pathophysiology involves an interplay between immune cells, such as T lymphocytes, and keratinocytes, which are the primary cells responsible for skin cell growth.

**Why the Correct Answer is Right**
Plaque psoriasis, also known as psoriasis vulgaris, is the most common type of psoriasis, accounting for approximately 80-90% of cases. It is characterized by well-defined, raised, red plaques with a silvery scale, typically found on the elbows, knees, scalp, and lower back. The exact mechanism is not fully understood, but it is believed to involve a complex interplay between genetic, environmental, and immune factors, including the activation of T lymphocytes and the release of pro-inflammatory cytokines.

**Why Each Wrong Option is Incorrect**
**Option A:** **Guttate psoriasis** is a type of psoriasis characterized by small, drop-like lesions, often triggered by streptococcal infections. While it is a common type of psoriasis, it is not the most common form.
**Option B:** **Pustular psoriasis** is a rare and severe form of psoriasis characterized by pus-filled bumps on the skin. It is not the most common type of psoriasis.
**Option C:** **Inverse psoriasis** is a type of psoriasis that appears as smooth, red patches in the folds of the skin, such as the armpits or groin. While it is a valid subtype of psoriasis, it is not the most common form.

**Clinical Pearl / High-Yield Fact**
Psoriasis is a systemic disease, and patients with psoriasis are at increased risk of developing other autoimmune conditions, such as psoriatic arthritis, inflammatory bowel disease, and lymphomas.

**Correct Answer:** C. Plaque psoriasis is the most common type of psoriasis.