The program to control the entry of illegal drugs into the country was a failure in 1987. If the program had been successful, the wholesale price of most illegal drugs would not have dropped substantially in 1987.
The argument in the passage depends on which of the following assumptions?
(A) The supply of illegal drugs dropped substantially in 1987.
(B) The price paid for most illegal drugs by the average consumer did not drop substantially in 1987.
(C) Domestic production of illegal drugs increased at a higher rate than did the entry of such drugs into the country.
(D) The wholesale price of a few illegal drugs increased substantially in 1987.
(E) A drop in demand for most illegal drugs in 1987 was not the sole cause of the drop in their wholesale price.
the program was a failure.
as a result, we are told that the price of most illegal drugs dropped substantially.
the argument makes a leap of faith, which is very vulnerable to critics. it states that the increased supply caused the drop in price.
we would thus need to look at an answer choice that would strengthen the argument while protecting it from any weakeners.
A possible weakener - price went down because the demand went down. Another one - price went down because the domestic production of drugs went up.
thus, an correct answer choice would provide information that the above is not true.
A - if the supply dropped, then the price would have increased. so no.
B - tricky but not. if negated, doesn't help much to weaken the argument. on the contrary, negated statements supports the argument. here the DID NOT - makes the answer choice incorrect.
C. just like B - this one is a weakener. negated answer would rather support the argument than weaken.
D. "of a few" makes this one incorrect. furthermore, it looks more like a weakener.
E. aha! so it was not the decreased demand that sent prices plunging.