Which of the Following Is a Fitness Trade-Off (Compromise)

Which of the following is a fitness trade-off (compromise) ?

A) In some hornbill species, the male helps seal the female in a tree with her nest until the young are ready to fledge.
B) Hummingbirds are the best pollinators of certain flowers, but bees are the best pollinators for orchids.
C) The strong, thick beak of a woodpecker helps it find insects in trees.
D) Turtle shells provide protection but are heavy and burdensome when moving.
E) Fruit bats are better pollinators of native fruit trees than birds are.