**Core Concept**
The patient's extremely high LDL cholesterol level indicates severe hypercholesterolemia, which is a major risk factor for atherosclerotic cardiovascular disease (ASCVD). Physical examination findings can provide clues about the presence and potential complications of hypercholesterolemia.

**Why the Correct Answer is Right**
The most likely finding on physical examination is xanthelasmata, which are small, yellowish patches or plaques on the skin, particularly on the eyelids. These are indicative of cholesterol deposition in the skin. Xanthelasmata are associated with elevated levels of LDL cholesterol and are a marker of atherosclerotic disease. The pathophysiology behind xanthelasmata involves the accumulation of cholesterol in the dermal layer of the skin, which is a result of the breakdown of LDL particles.

**Why Each Wrong Option is Incorrect**
**Option A:** Corneal arcus is a condition that involves the deposition of lipid in the cornea, but it is typically associated with aging and is not as strongly linked to high LDL levels as xanthelasmata.
**Option B:** Carotid bruits are indicative of atherosclerosis, but they are more commonly associated with carotid artery stenosis rather than being a direct result of hypercholesterolemia.
**Option C:** Aortic regurgitation is a cardiac condition that can be associated with aortic valve disease, but it is not a direct result of hypercholesterolemia.

**Clinical Pearl / High-Yield Fact**
Xanthelasmata are a key physical examination finding in patients with hypercholesterolemia, and their presence should prompt further evaluation for atherosclerotic disease.

**Correct Answer:** C.