What general physical feature distinguishes a Black horse's coat?

A Black horse's coat is distinguished by its characteristic deep, true black color, which often exhibits a bluish sheen in sunlight. This bluish tone is particularly noticeable under certain lighting conditions and is a hallmark of a well-groomed black coat. The richness of the black fur can create a striking visual effect, which differentiates it from other coat colors.

The other options describe characteristics associated with different coat colors or patterns. A reddish hue suggests a bay or chestnut color, mottled with white may refer to pinto or appaloosa patterns, and reflecting shades of brown is more typical of liver chestnut or dark bay horses. Each of these descriptions is not applicable to a true black horse, reinforcing the specific feature of the bluish cast in sunlight that defines its coat.