The correct option is A Lack cambium
Grafting
Grafting is a method of vegetative propagation in plants in which the root system and shoot system of two different plants are joined together to form a composite plant.
The scion (stem or bud) is grafted onto the stock (root bearing part) for this purpose.
Grafting disrupts the vascular system and regeneration of the vascular system is necessary to maintain normal transportation of water and nutrients.
Monocots have no vascular cambium, which is a lateral meristematic tissue capable of dividing and adding to secondary growth. Thus regeneration of tissues is impossible, making grafting impossible.
Final answer:
(a) Lack cambium