**Core Concept**
The question is testing the student's knowledge of a specific lysosomal storage disorder, which is a group of genetic disorders caused by the deficiency of lysosomal enzymes. The patient's symptoms and biopsy findings suggest a disorder involving the accumulation of a particular substance within histiocytes.

**Why the Correct Answer is Right**
The presence of histiocytes with PAS-positive, Diastase-resistant material in the cytoplasm is characteristic of Gaucher's disease, a lysosomal storage disorder caused by the deficiency of glucocerebrosidase enzyme. This enzyme deficiency leads to the accumulation of glucocerebroside within the lysosomes of histiocytes. Electron-microscopic examination of these histiocytes would likely reveal the presence of characteristic membranous structures called "membrane-bound lipid inclusions" or "Gaucher cells," which are a result of the accumulation of glucocerebroside.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is unrelated to the clinical presentation and biopsy findings described in the question. The presence of "lysosomal bodies" is not specific to any particular lysosomal storage disorder.
**Option B:** This option is incorrect because "lipofuscin" is a type of waste material that accumulates within cells over time, but it is not specific to Gaucher's disease or the clinical presentation described in the question.
**Option C:** This option is incorrect because "myelin figures" are a type of membranous structure that can be seen in various cellular conditions, but they are not specific to Gaucher's disease or the clinical presentation described in the question.

**Clinical Pearl / High-Yield Fact**
Gaucher's disease is an autosomal recessive disorder with a high prevalence among Ashkenazi Jews. It is caused by mutations in the GBA gene, which codes for the glucocerebrosidase enzyme. Gaucher's disease is characterized by the accumulation of glucocerebroside within histiocytes, leading to hepatosplenomegaly, anemia, and other systemic complications.

**Correct Answer:** D.