Which of the following treatments is best for restoring skin moisture?

Hydration is the most appropriate treatment for restoring skin moisture, as it directly addresses the skin's need for moisture replenishment. Hydration treatments typically involve the application of hydrating ingredients such as hyaluronic acid, glycerin, and various moisturizing creams and serums that help to bind water to the skin, thus enhancing its ability to retain moisture. This process effectively restores the skin's moisture barrier, making the skin look plumper, softer, and more youthful.

Exfoliation, while beneficial for removing dead skin cells and promoting cell turnover, does not directly provide moisture. Instead, it can sometimes lead to dryness if done excessively. Peeling treatments, which may involve chemical agents to slough off layers of skin, also do not focus on hydration and can potentially result in further moisture loss. Lightening treatments aim to reduce pigmentation and even out skin tone, but they do not target moisture restoration directly. Therefore, hydration is the best answer to maintain and restore moisture levels in the skin.