**Core Concept**
Osteoarthritis (OA) is a degenerative joint disease characterized by the breakdown and loss of articular cartilage, leading to joint pain and stiffness. It primarily affects weight-bearing joints and those subjected to repetitive stress.

**Why the Correct Answer is Right**
Osteoarthritis is not an inflammatory arthritis. It is a non-inflammatory, degenerative joint disease that results from the wear and tear of joint components over time. The primary pathophysiological process involves the loss of proteoglycans and collagen in the cartilage, leading to its progressive degeneration. Unlike inflammatory arthritides, OA does not involve significant inflammation or immune system activation.

**Why Each Wrong Option is Incorrect**
**Option A:** Osteoarthritis indeed involves synovial joints, which are joints enclosed in a synovial capsule containing synovial fluid.

**Option B:** While osteoarthritis does involve the breakdown of articular cartilage, the term "progressive softening" is not the most accurate description of this process. Cartilage degeneration in OA is characterized by a loss of matrix components and chondrocyte death.

**Option D:** Marginal osteophytes are a characteristic feature of osteoarthritis, representing bony growths that form in response to joint degeneration. These osteophytes can lead to joint pain and stiffness.

**Clinical Pearl / High-Yield Fact**
Osteoarthritis is a common cause of disability worldwide, and its management involves a multidisciplinary approach, including pharmacological, surgical, and non-pharmacological interventions. Understanding the pathophysiology of OA is crucial for developing effective treatment strategies.

**✓ Correct Answer: C. It is an inflammatory ahritis**