Question

A new and more aggressive form of the fungus that caused the Irish potato famine of the nineteenth century has recently arisen. However, since this new form of the fungus can be killed by increased application of currently used fungicides, it is unlikely that the fungus will cause widespread food shortages in countries that currently rely on potatoes for sustenance.
Which of the following, if true, most calls into question the conclusion in the argument above?

• A. Though potatoes are an important staple crop in many parts of the world, people in most countries rely primarily on wheat or rice for sustenance.
• B. Potato farmers in many countries to which the new form of the fungus has spread cannot afford to increase their spending on fungicides.
• C. The new form of the fungus first began to spread when contaminated potato seeds were inadvertently exported from a major potato-exporting country.
• D. Potato farmers in most countries use several insecticides on their crops in addition to fungicides of the sort that kill the new form of the fungus.
• E. Most governments have funds set aside that can be used to alleviate the effects of large-scale disasters such as severe food shortages and floods.

Hint:

To weaken an argument, look for the unstated assumption. Here, the assumption is that since a chemical solution exists, it will be used effectively. The correct answer often shows why this assumption is false (e.g., the solution is too expensive, unavailable, or has prohibitive side effects).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
This is a critical reasoning question that asks us to weaken an argument. The argument's structure is as follows:

Premise 1: A new aggressive potato fungus exists.
Premise 2: The fungus can be killed by \textit{increased application} of existing fungicides.
Conclusion: Therefore, widespread food shortages in potato-reliant countries are unlikely.
To weaken this argument, we need to find a statement that breaks the logical link between the premise (the existence of a solution) and the conclusion (the problem will be avoided). The core assumption is that the solution (increased fungicide) will be effectively implemented.
Step 2: Detailed Explanation:
Let's analyze the options to see which one attacks this assumption:


(A) This statement suggests the problem might not be as widespread globally, but it doesn't weaken the conclusion about the specific "countries that currently rely on potatoes". It sidesteps the core argument.

(B) This statement directly attacks the practicality of the proposed solution. If the farmers who need to apply the increased fungicide \textit{cannot afford to do so}, then the solution is ineffective in practice. This means that despite a theoretical solution existing, the fungus could still run rampant and cause the very food shortages the conclusion claims are unlikely. This is a very strong weakener.

(C) This explains how the problem started, but it doesn't challenge the conclusion about whether the problem can be controlled now. It's irrelevant to the argument's logic.

(D) The use of other chemicals like insecticides is irrelevant to the problem of a fungus and the effectiveness of fungicides. This option does not weaken the argument.

(E) This statement discusses a response to a disaster (food shortage) after it has already occurred. The argument's conclusion is that the shortage is \textit{unlikely to happen} in the first place. Government relief funds don't make the shortage itself less likely.

Step 3: Final Answer:
Option (B) is the only one that effectively calls the conclusion into question by pointing out a critical flaw in the implementation of the proposed solution. If the solution is unaffordable, it cannot be assumed to work.