Ava observes that a certain species of bird follows behind a herd of cattle. The bird species primarily eats insects. The birds stay with the herd of cattle as they graze.

What is a scientific hypothesis that Ava could formulate based on her observations?
A.
Why does this species of bird follow herds of cattle?
B.
The birds are happier around big herds of cattle rather than small herds.
C.
Do the birds get any benefit from following the herd of cattle?
D.
The birds follow the herd because the cows stir up insects for the birds to eat.