**Core Concept**
The eye's refractive surfaces are critical for focusing light onto the retina. The total number of refractive surfaces in the eye is a fundamental concept in ophthalmology, essential for understanding visual acuity and refractive errors.

**Why the Correct Answer is Right**
The correct answer is **6**. This is because the eye has six refractive surfaces: the anterior and posterior surfaces of the cornea, the anterior and posterior surfaces of the lens, and the anterior and posterior surfaces of the vitreous humor. The cornea and lens are the primary refractive surfaces, responsible for approximately 2/3 of the eye's total refractive power. The anterior and posterior surfaces of the vitreous humor also contribute to the eye's overall refractive power.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it underestimates the number of refractive surfaces in the eye.
* **Option B:** This option is incorrect because it overestimates the number of refractive surfaces in the eye.
* **Option D:** This option is incorrect because it does not accurately account for the refractive surfaces of the vitreous humor.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the cornea and lens are the primary refractive surfaces in the eye, accounting for approximately 2/3 of the eye's total refractive power.

**Correct Answer:** C. 6