Context: Read the passage. Then answer the question.

Guinea worms are a type of roundworm. Immature Guinea worms live in freshwater, and they are so tiny that they are visible only with a microscope. If a person drinks water that contains a worm, the worm is not digested. Instead, it can take refuge in the person's body and grow up to two feet long!
The mature worm creates a painful open wound in the person's skin. The person may put the wound in water to ease the pain. Then the worm releases its tiny offspring through the wound, into the water. If the offspring are released into drinking water, they can get inside another person's body.
Figure: a woman drinking through a straw that removes immature Guinea worms from water.
Which type of relationship is formed when a Guinea worm lives in a person's body?
A. mutualistic
B. commensal
C. parasitic
Choose the right answer from the options and respond with its letter.

C