**Core Concept**
Osteosarcoma and myositis ossificans are two distinct bone-related conditions that can be differentiated through radiological examination. Osteosarcoma is a primary malignant bone tumor, whereas myositis ossificans is a benign condition characterized by heterotopic ossification within muscle tissue.

**Why the Correct Answer is Right**
Radiologically, osteosarcoma can be differentiated from myositis ossificans by its characteristic appearance. Osteosarcoma typically presents as a lytic lesion with aggressive periosteal reaction and a "sunburst" pattern of bone formation, whereas myositis ossificans appears as a well-defined, peripheral, and metaphyseal lesion with a "rings and arcs" pattern of calcification. Additionally, osteosarcoma often involves the diaphysis and metaphysis of long bones, whereas myositis ossificans is commonly seen in the soft tissue surrounding joints.

**Why Each Wrong Option is Incorrect**
* **Option A:** Osteosarcoma and myositis ossificans can both present with lytic lesions, making this option incorrect as it does not provide a distinguishing feature.
* **Option B:** Myositis ossificans can also exhibit a periosteal reaction, but it is typically not as aggressive as that seen in osteosarcoma.
* **Option C:** The "rings and arcs" pattern of calcification is more characteristic of myositis ossificans, making this option incorrect as it describes a feature of the wrong condition.

**Clinical Pearl / High-Yield Fact**
When interpreting radiological images of bone tumors, it is essential to consider the patient's age, symptoms, and clinical history to narrow down the differential diagnosis.

**Correct Answer:** C.