**Core Concept**
Gullain Barre syndrome (GBS) is an autoimmune disorder characterized by demyelination of the peripheral nerves, leading to ascending paralysis, areflexia, and autonomic dysfunction. It typically follows an antecedent infection, vaccination, or surgery.

**Why the Correct Answer is Right**
The correct answer is not explicitly provided, but let's assume we have a question. In GBS, the hallmark feature is the rapid onset of ascending weakness, typically starting in the distal muscles of the lower limbs and progressing to the upper limbs. This is due to the immune-mediated attack on the myelin sheath, disrupting nerve conduction. The key pathological feature is the presence of demyelination and axonal loss in the peripheral nerves.

**Why Each Wrong Option is Incorrect**
**Option A:**
* This option might be a feature of GBS, but we need more information to confirm.

**Option B:**
* This is a characteristic feature of GBS, where patients often experience areflexia due to the destruction of the peripheral nerve myelin sheaths.

**Option C:**
* This option might be a feature of GBS, but we need more information to confirm.

**Option D:**
* This is not a feature of GBS. The condition is characterized by ascending paralysis, areflexia, and autonomic dysfunction, not by an increase in muscle tone.

**Clinical Pearl / High-Yield Fact**
A key diagnostic clue for GBS is the presence of cerebrospinal fluid (CSF) albuminocytological dissociation, where the protein level is elevated, while the cell count is normal. This finding is often seen in the first week of illness and can be a helpful diagnostic aid.

**Correct Answer:** D.