Context: Below is a food web from a tundra ecosystem in Nunavut, a territory in Northern Canada.
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 these organisms contains matter that was once part of the bilberry?
A. barren-ground caribou
B. short-tailed weasel
C. lichen
D. bear sedge
Answer with the option's letter from the given choices directly.

B