The correct answer for the question is option 2: Melanin. Melanin is the pigment responsible for giving color to human hair. It is produced by cells called melanocytes, which are located in the hair follicles. The amount and type of melanin present in the hair follicles determine the color of the hair. The two main types of melanin that contribute to hair color are eumelanin (which gives black and brown colors) and pheomelanin (which gives red and blonde colors). The ratio of these two types of melanin in the hair follicles determines the shade and intensity of the hair color. Higher concentrations of eumelanin result in darker hair, while higher concentrations of pheomelanin result in lighter hair. Melanin also plays a role in protecting the hair from UV radiation and environmental damage.