**Explanation:**

The correct answer to the question is option 'C' - Black.

**Eye Color Variations:**
The color of a person's eyes is determined by the pigmentation of the iris, which is the colored part of the eye. The iris contains a pigment called melanin, which is responsible for eye color. The amount and distribution of melanin in the iris determine the color of the eyes.

**Variations in Eye Color:**
1. **Blue Eyes:** People with blue eyes have low levels of melanin in their irises. The blue color is a result of light scattering and reflecting off the iris.
2. **Green/Hazel Eyes:** People with green or hazel eyes have a moderate amount of melanin in their irises. The combination of blue and green pigments in the iris results in these eye colors.
3. **Brown Eyes:** People with brown eyes have a higher concentration of melanin in their irises. The brown color is due to the abundant melanin pigments.
4. **Gray Eyes:** Gray eyes have a lower amount of melanin in the irises, giving them a grayish appearance.
5. **Amber Eyes:** Amber eyes have a unique golden or yellowish color due to the presence of a yellow pigment called lipochrome.

**Black Eyes:**
While black is not a common eye color, it is possible for some individuals to have extremely dark brown eyes that appear black. This is primarily due to the high concentration of melanin in their irises. The abundance of melanin pigments absorbs most of the light, making the eyes appear very dark.

**Conclusion:**
In conclusion, the correct answer to the question regarding the color of the eyes is option 'C' - Black. This answer is based on the understanding that black eyes can occur when there is a high concentration of melanin in the irises, resulting in a very dark appearance.

Black