Which of the following are the three main parts of the nail unit?

The three main parts of the nail unit are the nail plate, nail bed, and nail matrix. Among these, the nail matrix is particularly significant as it serves as the area where new nail cells are produced. These cells keratinize and eventually harden to form the nail plate, which is the visible part of the nail. The nail bed is the tissue beneath the nail plate that provides vital support and nourishment. Together, these parts collaborate to ensure proper nail growth and health.

The other options either include components that are not part of the main nail structure or mix terms that may confuse the understanding of the primary anatomy of the nail unit. For example, while the lunula is an important visible part of the nail matrix, it is not considered one of the main parts of the nail unit itself. Similarly, while the free edge and cuticle play roles in the protection and aesthetic aspects of the nail, they are not classified as the primary components that define the overall nail unit structure.