House cats suffering from hyperthyroidism——A condition characterized by weight loss, hyperactivity and eventually heart disease——often show high blood levels of polybrominated diphenyl ether (PBDE), a chemical used as a fire retardant in rugs and furniture covers. Clearly the use of PBDE for this purpose can contribute to hyperthyroidism in house cats.
Which of the following would, if true, most weakens the argument?
A Any sensitivity to PBDE that a house cat may have is at least partly based on genetic factors.
B Some animals other than house cats can develop hyperthyroidism when exposed to PBDE.
C House cat sometimes develop hyperthyroidism even when not exposed to PBDE.
D Some diseases other than hypothyroidism produce symptoms in house cats like those produced by hyperthyroidism.
E The effects of hyperthyroidism in house cat include an inability to expel PBDE from the blood.