Which of the following is essential before applying hairstyling products?

Ensuring hair is clean and free of debris is crucial before applying hairstyling products because it allows for optimal product performance and effectiveness. Clean hair enables products to distribute evenly and adhere properly, which is essential for achieving the desired style and maintaining it throughout the day. If there are any residues from previous products, dirt, or oils, this could not only inhibit the styling product from working as intended but also weigh the hair down and potentially lead to buildup over time.

While combing hair thoroughly, making the hair wet, and washing hair with soap are tasks that can prepare hair for styling, none of these steps addresses the critical aspect of having a clean base. Combing helps in detangling, making hair manageable, and wetting can assist in certain styling techniques, but without cleanliness, these steps are not as effective in the overall hairstyling process.