Question ID:PT37 S2 Q23 Passage:Roxanne:  To protect declining elephant herds from poachers seeking to obtain ivory, people concerned about such endangered species should buy no new ivory. The new ivory and old ivory markets are entirely independent, however, so purchasing antique ivory provides no incentive to poachers to obtain more new ivory. Therefore, only antique ivory‚ that which is at least 75 years old‚ can be bought in good conscience.Salvador:  Since current demand for antique ivory exceeds the supply, many people who are unconcerned about endangered species but would prefer to buy antique ivory are buying new ivory instead.  People sharing your concern about endangered species, therefore, should refrain from buying any ivory at all‚ thereby ensuring that demand for new ivory will drop. Stem:A point on which Roxanne's and Salvador's views differ is whether Correct Answer Choice:BChoice A:there are substances that can serve as satisfactory substitutes for ivory in its current uses Choice B:decreased demand for antique ivory would cause a decrease in demand for new ivory Choice C:people should take steps to avert a threat to the continued existence of elephant herds Choice D:a widespread refusal to buy new ivory will have a substantial effect on the survival of elephants Choice E:people concerned about endangered species should refuse to buy ivory objects that are less than 75 years old