The correct option is D Both A and C
Dicot roots have little or no pith and thus pith rays are not the source of interfascicular cambium. The parenchyma cells present between xylem and phloem elements in the vascular bundles constitute conjunctive tissue. The parenchymatous cells present beneath phloem take on meristematic activity and form cambial strands. Similarly, the cells of pericycle present against protoxylem divide and form multiple layers of cells, which are joined by cambial cells derived from conjunctive tissues and together they make a complete cambium ring. Thus, the correct answer is option D.