**Core Concept**
Benign hypertension can cause significant changes in the retina due to the increased pressure exerted on the retinal vessels. The retina is a highly vascularized tissue that is sensitive to changes in blood pressure, making it a useful indicator of systemic hypertension.

**Why the Correct Answer is Right**
The changes caused by benign hypertension in the retina include retinal hemorrhages, hard exudates, and cotton wool spots. These changes are due to the increased pressure in the retinal veins and arteries, leading to leakage of fluid and deposition of protein. The retina is particularly susceptible to these changes due to its delicate structure and high metabolic rate.

**Why Each Wrong Option is Incorrect**
**Option A:** Retinal detachment is a more severe and irreversible change that is typically associated with malignant hypertension or other underlying conditions. It is not a typical change caused by benign hypertension.
**Option B:** Retinal edema is a change that can be caused by benign hypertension, as the increased pressure leads to leakage of fluid into the retina.
**Option C:** Optic disc cupping is a change that is associated with glaucoma, not hypertension. While hypertension can cause changes in the optic disc, cupping is not typically one of them.

**Clinical Pearl / High-Yield Fact**
It's essential to note that the presence of retinal changes in a patient with hypertension can indicate a more severe underlying condition, such as malignant hypertension or other vascular diseases. A thorough evaluation of the retina is crucial in the management of patients with hypertension.

**Correct Answer: A. Retinal detachment.**