**Core Concept**
The refractive index of a medium is a measure of how much it bends light as it passes through. In the context of the eye, the refractive index is crucial for focusing light onto the retina. The eye has several components with different refractive indices, and the one with the maximum refractive index is essential for its function.

**Why the Correct Answer is Right**
The component of the eye with the maximum refractive index is the **vitreous humor**. This is because the vitreous humor is a gel-like substance that fills the space between the lens and the retina, and it has a refractive index of approximately 1.336. This high refractive index helps to focus light onto the retina, allowing for clear vision. The vitreous humor's high refractive index is due to its high concentration of water and its unique protein composition.

**Why Each Wrong Option is Incorrect**
**Option A:** The cornea has a refractive index of approximately 1.376, but it is not the component with the maximum refractive index. The cornea's high refractive index is due to its dense, compact structure.
**Option B:** The aqueous humor has a refractive index of approximately 1.336, which is similar to that of the vitreous humor. However, it is not the component with the maximum refractive index.
**Option C:** The lens has a refractive index that varies depending on its shape and composition, but it is generally lower than that of the vitreous humor.

**Clinical Pearl / High-Yield Fact**
The refractive indices of the eye's components are critical for its function. Remember that the vitreous humor has the maximum refractive index, and its unique composition helps to focus light onto the retina.

**Correct Answer: C. The lens has a refractive index that varies depending on its shape and composition, but it is generally lower than that of the vitreous humor.