**Core Concept**
The patient's presentation of xanthomas, hepatomegaly, and splenomegaly suggests a disorder involving abnormal lipid metabolism, leading to the accumulation of lipids in various tissues and organs.

**Why the Correct Answer is Right**
The patient's symptoms are characteristic of Familial Hypercholesterolemia (FH), a genetic disorder caused by mutations in the LDL receptor gene. This leads to impaired clearance of low-density lipoprotein (LDL) cholesterol from the bloodstream, resulting in elevated levels of LDL cholesterol. The accumulation of LDL cholesterol in the skin, liver, and spleen causes the formation of xanthomas and hepatosplenomegaly. The presence of xanthomas in clusters on the back, buttocks, and arms, legs is a classic feature of this condition.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not match the clinical presentation of the patient. Gaucher's disease is a lysosomal storage disorder caused by deficiency of glucocerebrosidase enzyme, leading to accumulation of glucocerebroside in macrophages, resulting in organomegaly and other systemic manifestations.

**Option B:** This option is incorrect because it does not explain the presence of xanthomas. Acute intermittent porphyria is a rare genetic disorder affecting the production of heme, leading to acute neurological symptoms and abdominal pain.

**Option C:** This option is incorrect because it does not match the clinical presentation of the patient. Homocystinuria is a genetic disorder caused by deficiency of cystathionine beta-synthase enzyme, leading to accumulation of homocysteine and methylmalonic acid in the urine, resulting in vascular and skeletal manifestations.

**Option D:** This option is incorrect because it does not explain the presence of xanthomas. Hemochromatosis is a genetic disorder caused by mutations in the HFE gene, leading to excessive iron absorption and accumulation of iron in various tissues and organs.

**Clinical Pearl / High-Yield Fact**
Familial Hypercholesterolemia is a genetic disorder with a high risk of premature cardiovascular disease, and early recognition and treatment are crucial to prevent its complications.

**Correct Answer:** C.