The correct option is D all the above
The tangential as well as radial walls of the endodermal cells have a deposition of water impermeable, waxy material-suberin-in the form of casparian strips. The primary function of casparian strips are
1. force water and minerals through the membranes of endodermal cells
2. prevent entry into the stele solely through the apoplast
3. provide regulation for water and minerals movement in the plants.