C
Below is a question with multiple-choice answers. Choose the correct option based on your reasoning.

### Question:
Charisma has a goldfish she keeps in a tank. She planted several underwater plants in the bottom of the tank. How are the goldfish and the plants in the tank similar?

### Choices:
A. Both add oxygen to the water.
B. Both perform photosynthesis.
C. Both are made up of cells.
D. Both eat food.

### Answer:
