**Core Concept**
Rheumatoid arthritis (RA) is a chronic autoimmune disorder characterized by inflammation and degeneration of the synovial joints, leading to pain, stiffness, and loss of function. The underlying pathophysiology involves a complex interplay between genetic predisposition, environmental triggers, and immune system dysregulation.

**Why the Correct Answer is Right**
Rheumatoid arthritis is typically characterized by symmetrical joint involvement, morning stiffness lasting more than an hour, and the presence of rheumatoid factor (RF) or anti-citrullinated protein antibodies (anti-CCP). The inflammation in RA leads to cartilage and bone destruction, resulting in joint deformities and disability. The characteristic "swan neck" deformity, also known as the "boutonniere" deformity, is a classic finding in RA.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because, although osteoarthritis (OA) is a distinct entity from RA, OA can also cause joint pain and stiffness. However, OA typically presents with asymmetric joint involvement, limited morning stiffness, and no systemic symptoms like fever or weight loss.
**Option B:** This option is incorrect because, while systemic lupus erythematosus (SLE) is an autoimmune disease like RA, SLE is characterized by a more widespread and unpredictable pattern of organ involvement, including skin, kidneys, and nervous system.
**Option C:** This option is incorrect because, although gout is a form of arthritis, it is typically characterized by acute, episodic joint pain, often in a single joint (the big toe), and is associated with elevated uric acid levels.

**Clinical Pearl / High-Yield Fact**
The "rule of nines" for joint involvement in RA states that if 5 or more joints are involved, the diagnosis is likely RA. Also, remember that the presence of rheumatoid factor or anti-CCP antibodies in a patient with joint pain and stiffness significantly increases the likelihood of RA.

**Correct Answer:** C