The correct option is : (b) suberin
Explanation:
Cork cambium is a secondary lateral meristem that may arise from permanent living cells of hypodermis or outer cortex. It is composed of a single layer of meristematic cells. Its cells divide tangentially and periclinally towards the outer surface and produce cork cells. These cells are compactly arranged and have thin cellulose walls in the beginning. As they mature there is a gradual loss of living matter and cells get elongated radially, vertically or tangentially. The cell walls become thick because of development of fatty substance called suberin, which is impervious to water.
