In maize, cross pollination occurs due to

Answer: Option A

In maize, cross pollination occurs due to Protandry.
When the pistil matures before anthers, it is called protogyny such as in pearl millet. When anthers mature before the pistil, it is known as protandry.
Protandry occurs in small, stable groups with essentially a monogamous relationship between one pair that reproduces. The largest males change sex, becoming females, and large females produce the greatest number of eggs.