A barnacle is a marine crustacean that attachets itself to a surface and stays in the same place its whole life. They feed on plankton by sweeping the water with their fan-like feet.
In this case, the barnacle attaches itself to the whales, by doing so, these organisms do not harm the whale, but are provided of a surface where they can filter food and live without being harmed themselves.
In this relationship, one organism, the barnacle, benefits, while the other organism, the whale, remains unaffected. This type of relationship is called "commensalism"
The correct answer is C.
