A Large Pharmaceutical Company has Recently Developed an Antibiotic that has been Shown to be Highly Effective at Treating a Variety of Infections.

Question: A large pharmaceutical company has recently developed an antibiotic that has been shown to be highly effective at treating a variety of infections. The drug is obtained from the scales of the rare tutu fish, which is only found in the wild living in the reefs off Sando Island in the South Pacific. Since it takes the scales from 1,000 fish to make a single kilogram of the antibiotic, it follows that continued production of the drug will lead to the extinction of the tutu fish.

Which of the following, if true, most seriously weakens the argument above?

1. The antibiotic made from the tutu fish’s scales is only available by prescription.
2. Because tutu fish are rare, they are also expensive.
3. The inhabitants of Sando island regard the meat of the tutu fish as a delicacy.
4. Tutu fish breed well in captivity and can be cultivated on fish farms.
5. Sando island is difficult to reach since it does not have an airstrip.

Answer: D

Explanation: This is a GMAT critical reasoning question. We have to find the option that most seriously weakens the argument above.

Let’s go through each of the available options and select the one that fits the best.

Option A: The antibiotic made from the tutu fish’s scales is only available by prescription.
Option A states that the antibiotic that is made from the tutu fish’s scales is available only by prescription. This statement is irrelevant to the argument presented in the passage as it does not matter if the antibiotic is available only by prescription. The argument is only concerned with the threat to the fish and if the product should be continued or not. Since this statement does not weaken the argument, Option A is incorrect.

Option B: Because tutu fish are rare, they are also expensive.
According to Option B, tutu fish are very rare and therefore, expensive. Again, this statement is not relevant to the argument. It does not talk about the threat the tutu fish face due to the production of the antibiotic and the fact that they might become extinct due to this practice. Since this statement does not weaken the argument presented in the passage, Option B is incorrect.

Option C: The inhabitants of Sando island regard the meat of the tutu fish as a delicacy.
Option C states that the residents of Sando island regard the meat of tutu fish as a delicacy. This statement presents a different kind of threat to the fish. But the argument only talks about the threat posed by the production of the drug. Since this threat is not relevant to the argument, Option C is incorrect.

Option D: Tutu fish breed well in captivity, and can be cultivated on fish farms.
Option D states that the tutu fish breed well in captivity and can be cultivated on fish farms. It directly attacks the author’s assumption. If the tutu fish can be bred well in captivity and can be cultivated on fish farms, their extinction can be avoided. This statement directly weakens the argument presented by the author. Since it weakens the argument, Option D is correct.

Option E: Sando island is difficult to reach since it does not have an airstrip.
Option E states that Sando island is difficult to reach because it does not have an airstrip. The way we can reach Sando island is not the concern of the argument. The argument only concerns how the production of the drug is posing a threat to the tutu fish and they can become extinct if the production goes on. So, Option E is incorrect.

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