**Core Concept**
Wernicke's encephalopathy is a neurological disorder caused by thiamine (Vitamin B1) deficiency, often seen in chronic alcoholics. The classical triad consists of confusion, ophthalmoplegia, and ataxia. Thiamine therapy is the cornerstone of treatment.

**Why the Correct Answer is Right**
The earliest symptom showing improvement from thiamine therapy is ophthalmoplegia, particularly nystagmus and gaze palsies. Thiamine acts by stabilizing neuronal membranes and promoting the activity of the enzyme transketolase, which is crucial for glucose metabolism in neurons. Improved glucose metabolism in the brain leads to rapid resolution of ophthalmoplegia within 24-48 hours of thiamine administration. This is followed by improvement in ataxia and confusion.

**Why Each Wrong Option is Incorrect**
**Option A:** Ataxia is the second symptom to show improvement, as it involves coordination and balance, which take longer to recover.
**Option B:** Confusion is the last symptom to improve, as it involves higher cognitive functions and may take several days to resolve.
**Option C:** This option is not provided in the question.

**Clinical Pearl / High-Yield Fact**
Wernicke's encephalopathy is a medical emergency that requires prompt recognition and treatment with thiamine. Early treatment can prevent the progression to Korsakoff's syndrome, a chronic and disabling condition characterized by memory loss and confusion.

**Correct Answer:** C.