Question ID:PT48 S4 Q3 Passage:Since 1989 the importation of ivory from African elephants into the United States and Canada has been illegal, but the importation of ivory from the excavated tusks of ancient mammoths remains legal in both countries. Following the ban, there was a sharp increase in the importation of ivory that importers identified as mammoth ivory. In 1989 customs officials lacked a technique for distinguishing elephant ivory from that of mammoths. Just after such a technique was invented and its use by customs officials became widely known, there was a dramatic decrease in the amount of ivory presented for importation into the U.S. and Canada that was identified by importers as mammoth ivory. Stem:Which one of the following is most strongly supported by the information above? Correct Answer Choice:DChoice A:Customs officials still cannot reliably distinguish elephant ivory from mammoth ivory. Choice B:Most of the ivory currently imported into the U.S. and Canada comes from neither African elephants nor mammoths. Choice C:In the period since the technique for distinguishing elephant ivory from mammoth ivory was implemented, the population of African elephants has declined. Choice D:Much of the ivory imported as mammoth ivory just after the ban on ivory from African elephants went into effect was actually elephant ivory. Choice E:Shortly after the importation of ivory from African elephants was outlawed, there was a sharp increase in the total amount of all ivory presented for importation into the U.S. and Canada.