**Core Concept**
The question is testing the student's knowledge of specific autoantibodies associated with Systemic Lupus Erythematosus (SLE), a chronic autoimmune disease characterized by the production of various autoantibodies.

**Why the Correct Answer is Right**
The correct answer is **Anti-dsDNA (double-stranded DNA) antibody**. This autoantibody is highly specific for SLE and is often used as a diagnostic marker. Anti-dsDNA antibodies are directed against the double-stranded DNA and are thought to play a role in the pathogenesis of lupus nephritis and other manifestations of SLE. The presence of high titers of anti-dsDNA antibodies is a hallmark of active disease and is often used to monitor disease activity and response to treatment.

**Why Each Wrong Option is Incorrect**
* **Option A:** Anti-Sm (Smith) antibody is highly specific for SLE but is not as sensitive as anti-dsDNA antibodies. While it is a useful diagnostic marker, it is not the most specific antibody for SLE.
* **Option B:** Rheumatoid factor (RF) is an antibody that is often present in patients with SLE, but it is also found in patients with rheumatoid arthritis and other autoimmune diseases. Therefore, it is not specific for SLE.
* **Option C:** Anti-SSA/Ro and anti-SSB/La antibodies are associated with Sjögren's syndrome and are not specific for SLE.

**Clinical Pearl / High-Yield Fact**
Anti-dsDNA antibodies are a key marker of SLE and are often used to monitor disease activity. High titers of anti-dsDNA antibodies are associated with active disease, while low titers are associated with remission.

**Correct Answer:** C. Anti-Sm (Smith) antibody