PT 60 S1 Q6

After an oil spill, rehabilitation centers were set up tosave sea otters ... ...

Which one of the following, as potential challenges, most seriously calls into question evidence offered in support of the conclusion above?
(A) Do sea otters of species other than those represented among the otters counted exist in areas that were not affected by the oil spill?
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Complete Section: LR-A, June '10 LSAT (PT 60 Sec. 1)