Context: Read the passage. Then answer the question.

Cleaner wrasse are small fish that live in tropical coral reefs. Wrasse are often visited by larger fish, such as moray eels.
When an eel visits a wrasse, the wrasse cleans the eel by eating parasites attached to the eel's body. If the parasites are not removed, the eel may become weak or even die.
Before the wrasse begins to clean, the eel opens its mouth to signal to the wrasse that it is ready to be cleaned. Then the wrasse eats all the parasites it can find on the eel's body, including those inside the eel's mouth!
Figure: a cleaner wrasse eating parasites from a moray eel's mouth.
Which type of relationship is formed when a cleaner wrasse eats parasites off a moray eel?
A. commensal
B. mutualistic
C. parasitic
Answer with the option's letter from the given choices directly.

B