Context: Read the passage. Then answer the question.

Tropical pitcher plants live in soil that is poor in nutrients. To get the nutrients it needs to survive, the plant uses a pitcher-shaped leaf as a trap to catch and digest small organisms. But the plant can also get nutrients from other sources, including from the feces of woolly bats.
A woolly bat can roost, or settle to sleep, in the upper part of the plant's trap. In the trap, the bat is protected from predators and bad weather. When the bat roosts, it can drop waste, including feces, into the bottom of the trap. The bottom of the trap holds a liquid that helps the plant digest the feces. The plant then absorbs nutrients from the digested feces.
Figure: a woolly bat approaching a tropical pitcher plant's trap.
Which type of relationship is formed when a woolly bat roosts in a tropical pitcher plant's trap?
A. commensal
B. parasitic
C. mutualistic
Select the correct answer from the provided options and reply with the letter associated with it.

C