Answer;
The Epidermis; stratum corneum layer
Step-by-step explanation;
The distal end of each digit is protected by a strong plate of hard keratin, called a nail or nail plate, which grows out from a nail bed. The nail bed, is a specialized form of skin epithelium, and has the same four layers of the epidermis of skin, with the nail plate being analogous to the stratum corneum layer.
The nail plate is made up of tightly packed, hard, keratinized epidermal cells. It has a nail body, a free edge, and extends deep into the dermis at the proximal end to form the nail root.