Which evidence did Ottowa scientists collect in researching PCB concentrations in Alaska?

A) PCBs were found in smaller concentrations in lakes where more salmon spawned.
B) PCBs were found in the same concentrations in lakes at similar altitudes.
C) PCBs were found in greater concentrations in lakes where more salmon spawned.
D) No PCBs were found in the lakes that were farthest from electronics industry dumping grounds.