When malaria rates in a tropical country are high, drug companies

Which of the following most logically completes the argument below?

When malaria rates in a tropical country are high, drug companies reduce the cost of many kinds of anti-parasite medications. The reason is that drug companies want to take in as much money as possible in medication sales so that they can invest the money into research for more profitable drugs. Anti-parasite drug cost reductions are likely to achieve this objective since __________.


(A) when prices decrease, more companies enter the market with competing anti-parasite drugs

(B) drug companies that spend a smaller percentage of revenues on research are unable to take advantage of anti-parasite drug cost reductions for this reason

(C) many more people will purchase anti-parasite medications if the price is lower than if the price remained the same

(D) an increase in the number of anti-parasite drugs sold raises the likelihood that some species of parasite will mutate so that the drug is not effective against it

(E) resulting research is unlikely to result in a malaria vaccine