What type of dye is commonly used on nylon fiber and is also used to color packaged foods and beverages?

The correct choice is acid dye. This type of dye is specifically designed for use on protein fibers and synthetic fibers like nylon. Acid dyes are water-soluble anionic dyes and are particularly effective for bright, vibrant colors that exhibit excellent colorfastness.

One of the noteworthy aspects of acid dyes is their wide range of applications, including their use in food and beverages. They share a commonality with certain food colorants due to their ability to adhere to similar chemical structures, making them suitable for a variety of coloring tasks in both textiles and consumables.

While other dyes such as disperse, reactive, and direct dyes have their unique properties and applications, they do not share the same characteristics and versatility as acid dyes in this specific context. Disperse dyes are mostly used for polyester and other synthetic fibers, while reactive dyes bond chemically with fibers like cotton and typically do not have the same application in food coloring. Direct dyes are used primarily for cellulosic fibers and do not exhibit the same affinity for nylon fibers as acid dyes do. Understanding these distinctions clarifies why acid dye is the most fitting answer.