I would say A) Coevolution because the two species would evolve in response to one another. Flowers and their pollinators must evolve together. For example, if the flower has a mutation that no longer attracts the bumblebees, it will not reproduce. Then the hummingbird would have to find a new food source.
Answer:
Plants have evolved several adaptations to life on land, including embryo retention, stomata, and vascular tissue
