**Core Concept**
Homer's syndrome, also known as Horner's syndrome, is a condition characterized by a disruption in the nerve pathways that control facial expressions, sweating, and eye movements. This syndrome results from damage to the sympathetic nerves that supply the face and head.

**Why the Correct Answer is Right**
The typical clinical features of Horner's syndrome include ptosis (drooping eyelid), enophthalmos (sinking of the eyeball into the orbit), and miosis (constricted pupil). These features are due to the loss of sympathetic innervation to the superior tarsal muscle, leading to ptosis, and to the dilator pupillae muscle, resulting in miosis. The loss of sympathetic tone also leads to enophthalmos. Nasal stuffiness is not a characteristic feature of Horner's syndrome.

**Why Each Wrong Option is Incorrect**
**Option B:** Ptosis is a characteristic feature of Horner's syndrome, resulting from the loss of sympathetic innervation to the superior tarsal muscle.
**Option C:** Enophthalmos is also a characteristic feature of Horner's syndrome, resulting from the loss of sympathetic tone to the orbital smooth muscle.
**Option D:** Nasal stuffiness is not a characteristic feature of Horner's syndrome, as it is primarily a disorder of the sympathetic nerves that control facial expressions and eye movements.

**Clinical Pearl / High-Yield Fact**
Horner's syndrome can be caused by damage to the sympathetic nerves from various sources, including tumors, trauma, or carotid artery dissection. Recognizing the characteristic features of Horner's syndrome is essential for diagnosing underlying conditions.

**Correct Answer:** ✓ Correct Answer: A. Dilated pupil