Which of the following, if true, most seriously undermines the advertisement’s argument?
(A) Some competing brands of painkillers are intended to reduce other kinds of pain in addition to sinus pain.
(B) Many hospitals that do not usually use Novex will do so for those patients who cannot tolerate the drug the hospitals usually use.
(C) Many drug manufacturers increase sales of their products to hospitals by selling these products to the hospitals at the lowest price the manufacturers can afford.
(D) Unlike some competing brands of painkillers, Novex is available from pharmacies without a doctor’s prescription.(D)
(E) In clinical trials Novex has been found more effective than competing brands of painkillers that have been on the market longer than Novex.
思路如下: most hospital give their patients Novex <> most effective
A) 無關 B)and E) support that Novex are more effective than other bands..
only C and D left
C) manufacturers provide low price - so attract more hospitals to use Novex
D) no need prescription -- easiler to obtain for patients

但答案是D)...
請指點一下~如何排除C
感恩~~