Context: Below is a food web from Little Rock Lake, a freshwater lake ecosystem in Wisconsin.
A food web models how the matter eaten by organisms moves through an ecosystem. The arrows in a food web represent how matter moves between organisms in an ecosystem.
Which of the following organisms is the secondary consumer in this food web?
A. green algae
B. water flea
C. rotifer
Select the correct answer from the given choices and respond with the letter of the chosen option.

C