Questions: Hair color is due to a pigment known as carotene keratin melanin hemoglobin

The answer is the third one: melanin.

Explanation for each option:

1. Carotene: This is a pigment found in plants that gives them an orange color, such as in carrots. It is not responsible for hair color in humans.

2. Keratin: This is a type of protein that makes up the structure of hair, skin, and nails. While it is a major component of hair, it does not determine hair color.

3. Melanin: This is the pigment responsible for the color of hair, skin, and eyes in humans. Different types and amounts of melanin result in the various hair colors seen in people.

4. Hemoglobin: This is a protein in red blood cells responsible for carrying oxygen throughout the body. It does not influence hair color.

In summary, melanin is the pigment that determines hair color.