Which of the following, if true, does most to help explain the oceanologist's doubt that the brevotoxins were the primary cause of the dolphins washing upon shore? A. Most stricken dolphins that wash upon shore, whether or not they eventually die, tend to do so in the Gulf of Mexico. B. Shortly before the dolphins washed ashore, a major oil spill not only caused algae to release brevotoxins but also released an array of deleterious industrial pollutants, including PCB. C. While PCB can cause metabolic imbalances in dolphins so that they stop eating prematurely, the dose of PCB a dolphin encounters in the wild is unlikely to pose a lethal threat to a dolphin. D. Scientists, near to the site of the beached dolphins, discovered a group of beach sea otters exhibiting similar symptoms as the dolphins. E. PCB and brevotoxins exercise different effects on an organism, with PCB causing visible lesions.