What is the primary function of an auxochrome in a dye?

Explanation

An auxochrome is a functional group attached to a chromophore that modifies the ability of the chromophore to absorb light, thus altering the color of the dye. It can also enhance the intensity or brightness of the color and improve the binding of the dye to the material being dyed. Option B is correct because it accurately describes these roles. Option A is incorrect because producing the initial color is the job of the chromophore. Option C is incorrect because solubility is not primarily affected by auxochromes, and Option D is incorrect because auxochromes do not serve as reducing agents.