**Core Concept**
Acute rheumatic fever (ARF) is a complication of untreated or inadequately treated group A beta-hemolytic streptococcal (GABHS) pharyngitis, characterized by an autoimmune response leading to inflammation and damage in various tissues.

**Why the Correct Answer is Right**
The mechanism of ARF involves molecular mimicry between the streptococcal M protein and host cardiac myosin. This cross-reactivity leads to the production of antibodies against the host's cardiac tissue, resulting in autoimmune inflammation and damage to the heart valves, joints, skin, and central nervous system. The autoimmune response is triggered by the T-cell response to the bacterial M protein, which shares structural similarities with the host's cardiac myosin.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe the autoimmune mechanism underlying ARF.
**Option B:** This option is incorrect because it refers to a different condition, Kawasaki disease, which is a distinct clinical entity.
**Option C:** This option is incorrect because it refers to a different mechanism of action, involving complement activation, which is not the primary mechanism of ARF.

**Clinical Pearl / High-Yield Fact**
ARF is a classic example of molecular mimicry, where the immune system's response to a bacterial infection leads to an autoimmune response against the host's own tissues. This concept is crucial in understanding the pathogenesis of ARF and other autoimmune diseases.

**Correct Answer:** C.