The correct option is
D Desirable characters of scion are transferred to stock.
Grafting is a horticultural technique used to join parts from two or more plants so that they appear to grow as a single plant. In grafting, the upper part (scion) of one plant grows on the root system (rootstock) of another plant.
In this process, desirable characters of scion are transferred to stock because the stock being root system cannot be uprooted as it decreases the survival rate.
So, the correct option is 'Desirable characters of scion are transferred to stock'.