Which nutrient deficiency is responsible for little leaf in mango and mottle leaf of citrus?

Correct option is A

The correct option is (a) Zinc. Little leaf in mango and mottle leaf in citrus are caused by zinc deficiency. Zinc is essential for leaf development, and its deficiency leads to smaller leaves with interveinal chlorosis.
(b) Phosphorus – Phosphorus deficiency affects root and flower development, not little leaf.
(c) Copper – Copper deficiency causes symptoms like wilting and dieback, but not little leaf.
(d) Magnesium – Deficiency leads to chlorosis in older leaves, but not little leaf.