**Core Concept**
Systemic Lupus Erythematosus (SLE) is a complex autoimmune disease characterized by the production of various autoantibodies. These autoantibodies target multiple components of the cell and nucleus, leading to inflammation and tissue damage. The disease activity in SLE is often correlated with the levels of specific autoantibodies.

**Why the Correct Answer is Right**
The correct answer is **Anti-DsDNA** (Anti-double-stranded deoxyribonucleic acid) antibodies. These antibodies are highly specific for SLE and are often used as a marker for disease activity. Elevated levels of Anti-DsDNA antibodies are associated with increased renal involvement, higher disease activity, and poorer prognosis in SLE patients. The mechanism behind this correlation is not fully understood, but it is believed that Anti-DsDNA antibodies contribute to the formation of immune complexes that deposit in the kidneys, leading to glomerulonephritis.

**Why Each Wrong Option is Incorrect**
**Option A:** Anti-Sm (Smith) antibodies are highly specific for SLE, but they do not correlate with disease activity. They are rather an indicator of the disease itself.
**Option B:** Anti-Ro (SS-A) antibodies are associated with SLE, but they are more commonly linked to Sjögren's syndrome and neonatal lupus. They do not directly correlate with disease activity in SLE.
**Option C:** Anti-SSB (La) antibodies are also associated with SLE, but they are more commonly linked to Sjögren's syndrome. They do not correlate with disease activity in SLE.

**Clinical Pearl / High-Yield Fact**
The presence of Anti-DsDNA antibodies in low titers (less than 100 IU/mL) does not necessarily indicate active disease. However, in the context of clinical symptoms and other laboratory findings, even low titers of Anti-DsDNA antibodies can be used to support the diagnosis of SLE.

**Correct Answer:** A. Anti-DsDNA antibodies.