**Core Concept**
Henoch-Schönlein purpura (HSP) is a form of vasculitis that affects small blood vessels, characterized by the deposition of IgA immune complexes, leading to inflammation and hemorrhage in the skin, joints, gastrointestinal tract, and kidneys.

**Why the Correct Answer is Right**
HSP typically presents with non-thrombocytopenic purpura, abdominal pain, arthritis, and renal involvement. The pathogenesis involves the activation of the complement system and the release of various cytokines, leading to inflammation and tissue damage. The deposition of IgA immune complexes in the affected tissues is a hallmark of HSP.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because HSP is not typically associated with thrombocytopenia. Instead, it is characterized by non-thrombocytopenic purpura.
**Option B:** This option is incorrect because while HSP can involve the kidneys, it is not typically associated with nephrotic syndrome. Instead, it can cause hematuria and proteinuria.
**Option C:** This option is incorrect because while HSP can involve the joints, it is not typically associated with a symmetrical polyarthritis. Instead, it can cause a migratory arthritis that affects the knees, ankles, and elbows.

**Clinical Pearl / High-Yield Fact**
HSP often affects children and young adults, and it is more common in males. The disease typically resolves spontaneously within weeks to months, but renal involvement can persist and require long-term follow-up.

**Correct Answer:**
Note: The correct answer was not provided in the question. Please provide the correct answer and I will complete the explanation accordingly.