The correct option is D all the above
Vascular bundles of monocot stem are conjoint, collateral (xylem, phloem both present together on the same radius, xylem towards the inside and phloem towards outside) but closed, i.e., they lack cambium; hence secondary growth is absent. Phloem consists of sieve tubes, companion cells, and a few phloem fibers. Phloem parenchyma is absent.