Cork cambium gives rise to
a)	Phellogen and secondary cortex	b)	Phellogen, phelloderm and secondary cortex
c)	Cork and phellogen	d)	Cork and secondary cortex

(d)

Cork cambium or phellogen cells divided perclinically cutting off cells towards the outside and inside. The cells cut off towards the outside become suberised and dead. These are compactly packed in radial rows without intercellular spaces and form cork or phellem. Cork is impervious to water due to suberin and provides protection to underlying tissues. The cells cut off from cork cambium towards inside add to the cortex and are called secondary cortex cells on phelloderm.