In a certain wildlife park, park rangers are able to track the movements of many
rhinoceroses because those animals wear radio collars. When, as often
happens, a collar slips off, it is put back on. Putting a collar on a rhinoceros
involves immobilizing the animal by shooting it with a tranquilizer dart. Female
rhinoceroses that have been frequently recollared have significantly lower
fertility rates than uncollared females. Probably, therefore, some substance in
the tranquilizer inhibits fertility.

In evaluating the argument, it would be most useful to determine which of the
following?

A: The dose of tranquilizer delivered by a tranquilizer dart is large enough to
give the rangers putting collars on rhinoceroses a general margin of safety
B: The fertility rate of uncollared female rhinoceroses in the park has been
increasing in the past few decades
C: The male rhinoceroses in the wild life park do not lose their collars as often
as the park's female rhinoceroses do.
D: The tranquilizer used in immobilizing rhinoceroses is the same as the
tranquilizer used in working with other large animals.
E: Any stress that female rhinoceroses may suffer as a result of being
immobilized and handled has little or no negative effect on their fertility

OA E