In the Arctic Ocean, the predominant primary producers are phytoplankton. Phytoplankton are consumed by zooplankton, which in turn are eaten by codfish. In years when there is more open water (less ice coverage), there are more zooplankton and fish than in years with less open water (more ice coverage). Based on the graph above, the difference is most likely because
(A) when there is less open water, light is blocked from the zooplankton, so they cannot produce as much food for the fish
(B) when there is more open water, the temperature is warmer, so the zooplankton and fish populations increase in size
(C) the ice blocks the light, so in years with more ice coverage, there is less photosynthesis by the phytoplankton
(D) the ice increases the light available for photosynthesis, so primary production increases and zooplankton populations increase in size
Answer: C