**Core Concept**
Guillain-Barré Syndrome (GBS) is an autoimmune disorder characterized by ascending paralysis, muscle weakness, and areflexia, resulting from a demyelinating polyneuropathy. The pathophysiology involves the immune system mistakenly attacking the myelin sheath surrounding peripheral nerve axons, leading to impaired nerve conduction and muscle dysfunction.

**Why the Correct Answer is Right**
GBS typically presents with ascending paralysis, starting from the lower extremities and progressing upwards, often accompanied by muscle weakness, areflexia, and sensory disturbances. The syndrome is usually preceded by an antecedent infection, such as Campylobacter jejuni, which triggers an autoimmune response against the peripheral nerves. The affected nerves are demyelinated, leading to impaired nerve conduction and muscle dysfunction.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not specified, please provide the options for the question.

**Clinical Pearl / High-Yield Fact**
GBS is a medical emergency, and prompt recognition and treatment are crucial to prevent respiratory failure and other complications. The syndrome is often reversible with immunotherapy, such as plasmapheresis or intravenous immunoglobulin.

**Correct Answer:**