The correct option is D Ca
Calcium is needed to the growing root tip. It is required in the formation of middle lamella of the cell wall present in the form of calcium pectate. When calcium is deficient, new tissue such as root tips, young leaves, and shoot tips often exhibit distorted growth from improper cell wall formation.
Iron is involved in the synthesis of chlorophyll, and it is essential for the maintenance of chloroplast structure and function.
Zinc is essential in the formation of auxins, which help with growth regulation and stem elongation.
Manganese is involved in pollen germination, pollen tube growth, root cell elongation and resistance to root pathogens.