Which of the Following Is Most Likely an Example of Coevolution

Which of the following is most likely an example of coevolution?

A) The color of a rodent's hair changes to better match a new environment.
B) A parasitic worm develops a new mechanism to attach to the gut lining of an organism that has a special adaptation designed to shed parasitic worms.
C) Two different species of plants produce flowers that are the same color,which attracts honeybees.
D) Two unrelated rodent species on different continents develop flaps of skin between their front legs and bodies that allow them to glide between trees.