The presence of microorganisms that produce a toxin causes seawater to turn brownish red, a phenomenon known as a red tide. Sea otters do not feed in areas where clams, their main source of food, have become contaminated with this toxin. According to a proposed explanation of the otters’ behavior, the otters sample the clams in a potential feeding area and can taste any toxin in them.
Which of the following, if true, would most ply indicate that the hypothesis described in the last sentence of the passage is not correct
A．In some of the areas where red tides occur, neither clams nor sea otters are indigenous species.
B．The presence of sea otters in a given area has a significant effect on which other marine organisms are to be found in that area.
C．When seawater in an area unaffected by red tide is artificially dyed brownish red, sea otters do not feed on the clams in that area.
D．If the clams in a given area are contaminated with toxins, sea otters move to other areas in search of food.
E．(E) Although very small amounts of the toxin produced during a red tide are not harmful, large doses can be fatal to animals the size of sea otters.
