The correct option is D cuticle
The outer surface of the epidermis is covered by a waxy coating called the cuticle. It prevents the loss of water. This is usually seen in the leaves and the stem and is absent in the roots. Trichomes are epidermal appendages. The guard cells are parenchymatous cells that are part of the stomata, a type of epidermis. The mesophyll is the layer between the two epidermal cell layers.