**Core Concept**
The refracting structures of the eye, including the cornea, lens, and aqueous humor, work together to form a homocentric system of lenses. This system is responsible for focusing light onto the retina, allowing for clear vision. The refractive power of each structure contributes to the overall refractive power of the eye.

**Why the Correct Answer is Right**
The cornea, being the first refracting structure encountered by light, has a significant refractive power. It has a refractive index of approximately 1.376, which is higher than that of air (1.000). This difference in refractive indices allows the cornea to bend light and contribute to the eye's overall refractive power. The cornea's refractive power is responsible for approximately 2/3 of the eye's total refractive power.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not provided, so we cannot evaluate its correctness.
* **Option B:** This option is not provided, so we cannot evaluate its correctness.
* **Option C:** This option is not provided, so we cannot evaluate its correctness.
* **Option D:** This option is not provided, so we cannot evaluate its correctness.

**Clinical Pearl / High-Yield Fact**
The cornea's refractive power is responsible for approximately 2/3 of the eye's total refractive power. This is why corneal refractive errors, such as myopia or hyperopia, can significantly impact vision.

**Correct Answer:** C.