**Core Concept**
The question is testing the student's knowledge of the specific location and types of bone tumors in the appendicular skeleton. The correct answer requires an understanding of the histogenesis of bone tumors and their relationship with the growth plates.

**Why the Correct Answer is Right**
The correct answer is a type of bone tumor that originates from the epiphysis, which is the part of the bone that is distal to the growth plate. This type of tumor is known as a **Chondroblastoma**. Chondroblastomas are benign cartilaginous tumors that typically occur in the epiphyses of long bones, particularly in the proximal humerus or distal femur. They are composed of immature cartilage cells and are thought to arise from the resting cartilage cells (chondrocytes) in the epiphysis.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify a tumor type that arises from the epiphysis. **Fibrous cortical defects** are benign fibro-osseous lesions that occur in the metaphysis, not the epiphysis.
**Option B:** This option is incorrect because **Osteoid osteoma** is a benign bone tumor that arises from the cortex, not the epiphysis.
**Option C:** This option is incorrect because **Osteosarcoma** is a malignant bone tumor that arises from the metaphysis, not the epiphysis.

**Clinical Pearl / High-Yield Fact**
Chondroblastomas are often asymptomatic and may be discovered incidentally on radiographs. They can cause pain and swelling in the affected limb, particularly if they are located in a weight-bearing bone.

**Correct Answer:** C. Chondroblastoma