What is the other name for the cork tissue
A. Phellogen
B. Phelloderm
C. Phellem
D. Periderm

Hint: Cork is a dead tissue outside the tree or plant which gets thicker with age. They are filled with air, tannins, and resins. There are different parts of periderm which collectively refer as phelloderm, phellogen, phellem.

Complete answer: In plants, the actual covering of the plant is the epidermis and the outermost covering (epidermis) is changed by a tougher layer called bark. The bark is composed of periderm, the cortex, and the phloem. The periderm is the outermost layer but actually made up of the cork. Cork is also known as phellem. The cork cambium is a meristematic layer that creates new cells through mitosis. It is found in between the cork and primary phloem. It is also called phellogen. It is the lateral meristem and is responsible for the growth of roots and stems. The main function of the cork cambium is to produce cork which is the tough protection to the plant. The cork cambium is also called bark cambium, pericambium, and phellogen. New cells produced from the inner layer (called phelloderm) and the outer layer (called cork). The cork cells change the epidermis in the roots and stems of woody plants. These cells get dead at maturity and are filled with air or with materials like resins or tannins. The cork is relatively tougher than the epidermis and acts as a better protective barrier against water loss, pathogens, and mechanical injuries.
Thus, the correct option is option C, i.e., phellem.

Note: The phellogen and phellem are both the same cells. The phellogen grows to become phellem (cork). The cork made by plants or trees are of great importance. They are used as bottle stoppers, hot pads, bulletin boards, etc.