**Core Concept**
Acute rheumatic fever (ARF) is an autoimmune inflammatory disease that occurs after a group A beta-hemolytic Streptococcus (GABHS) infection, leading to immune complex deposition and inflammation in the heart, joints, skin, and brain.

**Why the Correct Answer is Right**
The autopsy findings in ARF are characterized by the presence of Aschoff bodies, which are granulomatous lesions composed of an outer layer of macrophages and an inner layer of lymphocytes and plasma cells. The valves of the heart, particularly the mitral and aortic valves, are often affected, leading to rheumatic heart disease (RHD). RHD is characterized by fibrosis and scarring of the valve leaflets, resulting in stenosis or regurgitation. In addition, the brain may show evidence of Sydenham's chorea, a manifestation of ARF characterized by involuntary movements and emotional changes.

**Why Each Wrong Option is Incorrect**
**Option A:** Aschoff bodies are a hallmark of ARF and are expected to be found at autopsy.
**Option B:** Rheumatic heart disease (RHD) is a common complication of ARF and can lead to valve damage and dysfunction.
**Option C:** Sydenham's chorea is a manifestation of ARF that can be seen on autopsy, particularly in the brain.

**Clinical Pearl / High-Yield Fact**
ARF is a preventable disease, and early treatment of GABHS infections with penicillin can prevent the development of ARF and RHD.

**Correct Answer: D.**