White bud of maize is due to deficiency of

Correct option is C

Zinc deficiency in maize causes characteristic “white bud” symptom.
The central whorl leaves turn white or pale yellow in early stages.
Zinc is essential for auxin synthesis and enzyme activation.
Deficiency affects leaf expansion and chlorophyll formation.
This disorder is commonly seen in alkaline and calcareous soils.
Therefore, zinc deficiency is the correct cause.