According to This Figure, Which Organisms Have the Highest Concentration

Multiple Choice

According to this figure, which organisms have the highest concentration of PCBs, and why?

A) phytoplankton, because they are at the bottom of the food chain
B) herring gulls, because they are at the bottom of the food chain
C) herring gulls, because they are at the top of the food chain
D) smelt, because they are in the middle of the food chain