**Core Concept**
The 'sunflower cataract' is a characteristic ocular manifestation of a systemic disease, specifically amyloidosis. It is a type of cataract that resembles a sunflower in appearance, with a characteristic petal-like configuration of lens fibers. This condition is associated with the deposition of amyloid proteins in the lens, leading to opacification and vision impairment.

**Why the Correct Answer is Right**
Amyloidosis is a systemic disease characterized by the deposition of amyloid proteins in various tissues, including the lens of the eye. The amyloid proteins accumulate in the lens fibers, leading to the formation of a characteristic 'sunflower cataract'. This type of cataract is often associated with primary amyloidosis, also known as AL amyloidosis, which is caused by the production of abnormal light chains by plasma cells. The deposition of amyloid proteins in the lens disrupts the normal structure and function of the lens, leading to the development of a sunflower cataract.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the 'sunflower cataract' is not typically associated with diabetes mellitus. While diabetes can cause cataracts, the characteristic sunflower appearance is not a common feature of diabetic cataracts.

**Option B:** This option is incorrect because the 'sunflower cataract' is not typically associated with trauma to the eye. Trauma can cause a variety of cataract types, but the sunflower cataract is not a common result of eye injury.

**Option C:** This option is incorrect because the 'sunflower cataract' is not typically associated with systemic hypertension. While systemic hypertension can cause a variety of ocular complications, the sunflower cataract is not a common feature of hypertensive retinopathy.

**Option D:** This option is incorrect because the 'sunflower cataract' is not typically associated with age-related macular degeneration. While age-related macular degeneration can cause vision loss, the sunflower cataract is not a characteristic feature of this condition.

**Clinical Pearl / High-Yield Fact**
The 'sunflower cataract' is a classic example of a systemic disease manifestation in the eye. It is often associated with primary amyloidosis, and its presence should prompt a search for underlying systemic disease. Remember that the sunflower cataract is a distinctive and characteristic finding that can help diagnose amyloidosis.

**Correct Answer:** C.