by bbirdwell Mon Jan 03, 2011 6:05 pm
The short answer to your question is that (D) cannot be right because we have no evidence in either argument of a "substantial effect on the survival of elephants."
Even if you ignore the "survival of.." part of the answer choice and ballpark it, you should not choose this answer. If anything, Roxanne thinks that refusal to buy new ivory is a good thing for elephants, and Salvador thinks that refusal to buy any kind of ivory is a good thing for elephants. Therefore, they would actually be likely to agree on this point.
To understand why (B) is correct, let's get the arguments straight:
Roxanne:
1. People who care about elephants should not buy new ivory.
2. Markets for new ivory and old ivory are totally independent.
3. Because of (2), buying old ivory does not provide an incentive to poachers, and it is therefore ok to buy old ivory.
Salvador:
1. Demand for old ivory is greater than supply.
2. People who don't care about elephants are buying new ivory since old ivory is not available.
3. People who care about elephants should not buy old ivory, which will cause the demand for new ivory to stop. (ostensibly because then old ivory would be available to the people who don't care about elephants)
Now, consider each point and ask yourself if the other party would agree or disagree -- keeping in mind that you may not know either way.
Roxanne
1. Salvador would definitely agree.
2. We don't know what Salvador thinks.
3. Salvador definitely disagrees -- he thinks concerned people should buy no ivory at all.
Salvador
1. We don't know what Roxanne's opinion is.
2. Ditto.
3. Roxanne definitely disagrees.
Now, at least in our minds, it's clear. We cannot predict what the correct answer will say, but it must somehow say that these two disagree about the purchase of old ivory and what effect it might have.
(B) is exactly what Salvador says in his conclusion. Roxanne, however, thinks that the markets are entirely independent, which contradicts this statement.
