Concept:The borer hides inside the maize stem, so destroying infected plants removes the pest and breaks its life cycle.
Explanation:The maize stem borer feeds and lives within the maize stem.
Hand-picking only removes pests found on the outside, not those hidden inside.
Physical barriers and scarecrows do not affect insects that are inside the plant.
Destroying and burning affected crops kills the larvae and pupae present within the stems.
This prevents the borer from spreading to healthy plants.
Therefore, the most effective control is to destroy and burn all affected crops.
Answer:A. destroying and burning all the affected crops