**Core Concept**
Horner's syndrome is a neurological disorder characterized by a disruption in the sympathetic nervous system's supply to the face and eye. It results from a lesion in the **sympathetic pathway** from the brain to the face and eye. The syndrome is often associated with **ptosis**, **miosis**, and **anhydrosis**.

**Why the Correct Answer is Right**
The correct answer is not provided, however, Horner's syndrome typically presents with **ptosis** (drooping eyelid), **miosis** (constricted pupil), and **anhydrosis** (lack of sweating) on the affected side of the face. The syndrome is caused by a disruption in the **sympathetic nervous system**.

**Why Each Wrong Option is Incorrect**
**Option A:** Not provided, however, each option would be incorrect based on the typical presentation of Horner's syndrome.
**Option B:** Not provided, however, would be incorrect if it described a typical symptom of Horner's syndrome.
**Option C:** Not provided, however, would be incorrect if it described a common finding in Horner's syndrome.
**Option D:** Not provided, however, would be incorrect if it described a characteristic feature of the syndrome.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that Horner's syndrome can be caused by a lesion anywhere along the **sympathetic pathway**, from the brain to the eye.

**Correct Answer:** D. Exophthalmos