What type of products cover the nail plate with a hardened film?

The correct answer is coatings, as these products are specifically designed to form a hardened film on the nail plate. Coatings are often formulated with ingredients that provide durability and protection, effectively sealing the nail surface and enhancing its appearance. They can serve various purposes, such as providing a glossy finish, adding color, or acting as a protective barrier against environmental factors.

While nail polish also covers the nail plate, it typically does not have the same emphasis on creating a long-lasting, hardened film as coatings do. Nail polish is primarily focused on color and may require a top coat for enhanced durability. Finishing creams, on the other hand, generally aim to provide a soft, smooth finish rather than a hardened layer and are not designed to form a protective film over the nail itself. Top coats, although related, generally serve as a finishing layer applied over nail polish to add shine and protection but do not encompass the broader category of coatings that can include various formulations to achieve a hardened effect.