Landfills naturally release methane gas as the waste stored in them de

­Landfills naturally release methane gas as the waste stored in them decays. Such decay is greatly accelerated by contact with rainwater. Some landfill operators use technology to extract methane before it escapes into the atmosphere, but this is an expensive process. A less expensive process, phytocapping, involves placing a layer of soil and dense vegetation on top of a landfill. This prevents most water from reaching the waste and could prevent the production and release of methane. Therefore, in order to reduce methane emissions in the most financially sound manner, landfill operators should adopt this alternative.

The conclusion of the argument is the following:

in order to reduce methane emissions in the most financially sound manner, landfill operators should adopt this alternative (phytocapping)

The support for the conclusion is the following:

this (using technology to extract methane before it escapes into the atmosphere) is an expensive process

A less expensive process, phytocapping, involves placing a layer of soil and dense vegetation on top of a landfill. This prevents most water from reaching the waste and could prevent the production and release of methane.

So, the reasoning of the argument is basically that phytocapping, rather than capturing methane, is the most financially sound way to reduce methane emissions because phytocapping is less expensive.

Which of the following would it be most useful to determine in order to evaluate the reasoning above?

This is an Evaluate question, and the correct answer will be the choice such that different answers to the question it presents weaken or strengthen the case for the conclusion.

A) Whether methane gas is produced by other human-influenced sources

The conclusion is specifically about how to reduce methane emissions from landfills.

What works best for reducing such emissions is not affected by whether methane is produced by other human-influenced sources. After all, regardless of what other sources of methane gas exist, in the specific case of landfills, phytocapping may be the most financially sound way to reduce methane emissions.

So, neither a yes nor a no answer to this question affects the case for the conclusion.

Eliminate.

B) Whether a combination of the methods would eliminate methane emissions

The answer to this question would certainly be helpful in determining the most EFFECTIVE way to COMPLETELY ELIMINATE methane emissions.

However, we are not looking for information that helps with determining how to completely eliminate methane emissions. We need information that helps with determining whether it makes sense to conclude that phytocapping is the most FINANCIALLY SOUND way to REDUCE methane emissions.

So, notice that information on whether a combination of the methods would eliminate methane emissions doesn't help with evaluating the argument. After all, regardless of whether a combination of the methods would eliminate methane emissions, it still may or may not be the case that, among the available methods - capture, phytocapping, or a combination - the one that is most financially sound for reducing, rather than eliminating, methane emissions is phytocapping, since it's less expensive than capture, or a combination for that matter.

Eliminate.

C) Whether other gases are released into the atmosphere as landfill waste decays

While this information may be important to a landfill operator, the conclusion of this particular argument is specifically about the most financially sound way to reduce methane emissions.

So, since its not clear that release of other gases from landfills would affect what is the most financially sound method for reducing methane emissions, the answers to this question don't help with evaluating the argument.

If this choice presented a different question related to other gases, such as whether a landfill operator could save money by solving multiple gas-related problems at once by using capture or phytocapping, then the answer to this question might be helpful in determining whether one method or the other is more financially sound.

However, without such additional detail, this question doesn't help with evaluating the argument, and we have to be careful not to make up a convoluted, unsupported story about other gases to somehow make the answers to this question seem relevant.

Eliminate.

D) Whether people consider current levels of landfill methane emissions to be harmful

Notice that the argument is not about whether reducing landfill emissions is important or worthwhile. The argument is only about the most financially sound way to reduce methane emissions from landfills.

So, how harmful people consider methane emissions is not relevant to this argument since that information doesn't affect what method of reducing methane emissions is most financially sound.

In other words, the answer to this question could help with determining whether reducing methane emissions itself makes financial sense, but the argument is not about whether reducing methane emissions makes financial sense. It's about the best method for a landfill operator to use if that landfill operator has decided that reducing methane emissions does make sense.

So, this choice helps with evaluating the case for a conclusion different from the conclusion of this argument.

Eliminate.

E) Whether methane gas captured from landfills can be sold profitably as a fuel source

This choice is interesting.

The conclusion that phytocapping is the most financially sound way to reduce methane emissions is based on the fact that phytocapping is less expensive than capturing methane.

At the same time, expense is only one aspect of a method being financially sound. Another aspect could be revenue or overall profitability.

So, a yes answer to this question could weaken the case for the conclusion. After all, if methane gas captured from landfills CAN be sold profitably as a fuel source, then the  revenue from selling the captured methane could offset the expense of capturing the methane or even make capturing methane a profitable operation, in which case capturing methane would be more financially sound than phytocapping, which involves some expense and likely would never be profitable.

On the other hand, a no answer to this question would strengthen the argument by helping to confirm that capturing methane is not going to be profitable for landfill operators and that, therefore, they will be better off financially if they phytocap to reduce methane emissions.

So, different answers to this question weaken or strengthen the case for the conclusion, and thus this choice helps with evaluating the argument.

Keep.

Correct answer: E­