Explanation:

phellogen

A.Cork cambium(phellogen) – a ring of meristematic tissue formed by the dedifferentiation of parenchyma present in the cortex of dicot stem. It produces cork or phellem towards the outer side and secondary cortex or phelloderm towards the inner side.

B.Vascular cambium – a ring of meristematic tissue formed by the joining of intra and interfascicular cambia. It produces secondary phloem towards the outer side and secondary xylem towards the inner side.

C.Phloem – food conducting complex tissue.

D.Xylem – water conducting complex tissue.