The sea otter is a keystone species in its aquatic environment. Which of the following statements BEST describes how the sea otter functions in its ecosystem?
A. The sea otter is the primary food source and balances the ecosystem.
B. The sea otter is the predator and balances the ecosystem.
C. The sea otter is the foundation and balances the ecosystem.
D. The sea otter is a producer and balances the ecosystem.