Which of the following is an example of mutualism?

AOxpeckers (bird) feed on the ticks found on a rhinoceros. Both species benefit. The oxpecker gets food and the rhino gets rid of a parasite.

BA flea feeds on a mouse’s blood to the mouse’s detriment

CHermit crabs will move into an old abandoned shell when their shell is no longer big enough to contain them. As the shell is inanimate (not living) it is not affected by this relationship

DBarnacles create home sites by attaching themselves to whales. As the barnacle is a filter feeder, it also gets access to more water (and more food) due to the relationship. Whale is unaffected