Which coloring agent is often used in food and cosmetics?

Carmine is a coloring agent derived from the cochineal insect, and it is commonly used in both food and cosmetics for its vibrant red hue. In the food industry, it serves as a dye in products such as yogurts, candies, and beverages, while in cosmetics, it can be found in products like lipsticks and blushes to provide a rich color. Its natural origin and strong coloring properties make it a popular choice among manufacturers aiming to achieve specific aesthetic qualities in their products.

Other options, such as benzalkonium chloride, are primarily utilized as disinfectants or preservatives rather than colorants. Sodium citrate functions mainly as a buffering agent and preservative in food; it does not serve as a coloring agent. Rhabdomyoma is not relevant, as it is a type of tumor found in muscle tissue and has no application in coloring food or cosmetics. Thus, carmine stands out as the correct answer due to its widespread acceptance and use in enhancing the visual appeal of food and beauty products.