Why Is It Believed That the Storage of Food for Later

Why is it believed that the storage of food for later use is an example of convergent evolution across species of birds?

A) The hippocampus is enlarged in food-storing birds.
B) Families of birds that store food are no more closely related to other food-storing families than they are to families of birds that do not store food.
C) Some species that store food do not have enlarged hippocampi.
D) Spatial memory is not important to species that do not store food.