E for me.

C is contradicting the argument.

In E, if there are competing maize eating insects that feed on milkweed plants, then even these insects would be dieing. This will help evaluate the argument.

C.

the ques asks if the farmer is putting the monarch butterflies at risk...
E is slightly weaker in the sense that even if maize-eating insects compete with monarch butterflies, it does not completely eliminate the risk of the latter feeding and dying.

C. I would stick with the scope when its confusing. So I ignore "other" insects.
What is OA?

Note that the author talks of caterpillars dying from feeding on the leaves laden with pollen but in conclusion, says, all monarch butterflies are in danger. There is a scope shift in the argument. Therefore, to evaluate his conclusion, D sounds the best.

Wouldn't using the "variance test" from Powerscore CR Bible on E mean - Yes the insects compete and use up all the pollen first, therefore the caterpillars don't die. Conversely, No, they don't compete and don't use the pollen therefore the caterpillars will use and die.

Argument Analysis :

Certain genetically modified strains of maize produce a powerful natural insecticide. A background information.
The insecticide occurs throughout the plant, including its pollen. A background information.
Maize pollen is dispersed by the wind and frequently blows onto milkweed plants that grow near maize fields. A background information. Milkweed plants – new actor in the argument
Caterpillars of monarch butterflies feed exclusively on milkweed leaves. A background information. Caterpillars – one more actor related to Milkweed plants.
When these caterpillars are fed milkweed leaves dusted with pollen from modified maize plants, they die. A background information – impact of modified strains of maize
Therefore, by using genetically modified maize, farmers put monarch butterflies at risk. Conclusion.

Assumptions -
a. Maize pollen is dispersed by the wind and frequently blows onto milkweed plants.
Assumes that pollens stay as well and wind is not strong enough to disperse pollens in short span of time or may be rain followed by wind to remove the pollens.
b. Caterpillars of monarch butterflies feed exclusively on milkweed leaves:
To remove / reduce the impact of pollens, Milkweed does not produce any natural defense such as chemical etc., which may affect caterpillars.
c. Caterpillars of monarch butterflies feed exclusively on milkweed leaves : maize and milkweed are grown in the same season hence pollens impact the caterpillar feeds.
d. Amount of pollens are significantly enough to impact the caterpillars.

Question stem :
Which of the following would it be most useful to determine in order to evaluate the argument?

A. Whether the natural insecticide is as effective against maize-eating insects as commercial insecticides typically used on maize are – Argument is about impact on caterpillar
B. Whether the pollen of genetically modified maize contains as much insecticide as other parts of these plants – So what only pollens are dispersed
C. Whether monarch butterfly caterpillars are actively feeding during the part of the growing season when maize is releasing pollen –
Yes : then argument is strengthened
No : then argument is weakened

D. Whether insects that feed on genetically modified maize plants are likely to be killed by insecticide from the plants pollen – So what .Impact on other insects is not good enough to conclude about caterpillars
E. Whether any maize-eating insects compete with monarch caterpillars for the leaves of milkweed plants growing near maize fields – Let them compete …where is impact of pollen?

Option C

I like C. Undermines the conclusion if true.

The crux of this argument is that genetically modified maize kills the caterpillars which eat the leaves dusted with poisonous pollen.

The only answer that works in our favor to decide if genetically modified maize will hurt the caterpillars is to find out if the leaves are harmful during the butterfly spawning season. Answer C will help us. If we find out that yes, the caterpillars feed when the pollen release is at its peak, we can conclude that g-mod maize is hazardous to monarch butterflies. If not, it does not cause the caterpillars as much harm as the statement claims.
_________________

Conclusion: Farmers are putting monarch butterflies at risk by using genetically modified maize.


A. Whether the natural insecticide is as effective against maize-eating insects as commercial insecticides typically used on maize are. Comparison with commercial insecticides is out of scope of the passage.
B. Whether the pollen of genetically modified maize contains as much insecticide as other parts of these plants. These Caterpillars feed exclusively on pollen laden milkweed leaves. Concentration of insecticide on other parts of maize is immaterial.
C. Whether monarch butterfly caterpillars are actively feeding during the part of the growing season when maize is releasing pollen. This is the best choice.If the caterpillars are actively feeding during pollination time then modified maize is a risk to caterpillars.
D. Whether insects that feed on genetically modified maize plants are likely to be killed by insecticide from the plant's pollen. We are exclusively talking about monarch butterflies. Knowing about insects in general will not help us evaluate the argument.
E. Whether any maize-eating insects compete with monarch caterpillars for the leaves of milkweed plants growing near maize fields. If some maize-eating eating insects are competing with monarch caterpillar for leaves of milkweed plants, then we can say that probably maize-eating insects are a risk to caterpillars and its got nothing to do with farmers. This option is very vague.