Final answer:
A clarifying shampoo is used to remove product buildup from the hair and scalp, containing surfactants like sodium lauryl sulfate for deep cleansing.
Step-by-step explanation:
The shampoo most likely used to remove product buildup is a) Clarifying shampoo. This type of shampoo is specifically designed to cleanse the hair and scalp deeply, removing not only sebum but also accumulated product residue like hairsprays, gels, and conditioners. It contains surfactants such as sodium lauryl sulfate or sodium laureth sulfate that act as detergents to effectively cleanse the hair.
While other types of shampoos like moisturizing shampoo, volumizing shampoo, and color-protecting shampoo address specific hair needs such as hydration, added volume, and color retention, they are not formulated with the purpose of removing heavy build-up like a clarifying shampoo.