**Core Concept**
Acute rheumatic fever (ARF) is an autoimmune inflammatory disease that occurs after a group A beta-hemolytic streptococcal (GABHS) infection, typically pharyngitis. It involves the heart, skin, joints, and brain, and is characterized by the presence of autoantibodies against host tissues.

**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of ARF, which is a classic example of molecular mimicry. In ARF, the immune system produces antibodies against the GABHS M protein, which cross-react with cardiac tissues, leading to inflammation and valvular damage. The Jones criteria, which are used to diagnose ARF, include major and minor criteria, such as carditis, migratory polyarthritis, and erythema marginatum.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is a true statement about acute rheumatic fever. The disease is indeed more common in developing countries where access to healthcare is limited.
**Option B:** This option is incorrect because the major criteria for diagnosing ARF include carditis, polyarthritis, and chorea, but not myocarditis. While myocarditis can occur in ARF, it is not a major criterion.
**Option C:** This option is true and is one of the major criteria for diagnosing ARF.
**Option D:** This option is incorrect because the Jones criteria do not include a requirement for a preceding streptococcal infection as a major criterion, although it is a necessary prerequisite for the diagnosis.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the Jones criteria are used to diagnose ARF, and they include both major and minor criteria. The major criteria include carditis, polyarthritis, and chorea, while the minor criteria include fever, arthralgia, and a prolonged PR interval.

**Correct Answer: B. Myocarditis**