If the county continues to collect residential trash at current levels

If the county continues to collect residential trash at current levels, landfills will soon be overflowing, and parkland will need to be used in order to create more space.
The condition: The county continues to collect residential trash at the current rate
The consequence: Landfills will soon be overflowing, and parkland will need to be used to create space for the extra trash.

Charging each household a fee for each pound of trash it puts out for collection will induce residents to reduce the amount of trash they create;
This statement is a prediction; it says X will lead to Y.

X: charging each household a fee per pound of trash it gives for collection

Y: Residents will be encouraged to reduce the amount of trash they create

(As I read this statement, I can already observe a difference between “the trash it gives for collection” and “the trash they create.” I can see that people may find a way to save the amount they pay by reducing the amount of trash they give to collection but keep producing the same amount of trash. Maybe, they’ll dispose of the remaining trash on their own)

this charge will therefore protect the remaining county parkland.
The author concludes that this charge will protect the remaining county parkland.

The Gist:

Charging each household a fee for each pound of trash it puts out for collection will reduce the amount of trash the residents generate and thus will protect the remaining county parkland.

The Gaps

1. As I shared in the passage analysis, the residents may find a way to dispose of their trash in some way other than giving it for collection and may continue to generate the same amount of trash. In such a case, our plan will not reduce the amount of trash the residents generate.
2. It could also be the case that the households are completely comfortable with paying the fee. As a result, they don’t reduce the amount of trash that they generate.

(A) Residents will reduce the amount of trash they put out for collection by reducing the number of products they buy

Incorrect. -Let me first discuss a variation of this option:

A’: Residents will reduce the amount of trash they put out for collection

Is A’ an assumption?

I don’t think so. Let me explain.

The argument says that X (charging each household for the trash it generates) will lead to Y (reduction in the amount of residential trash). Thus, X will help.

A’ says that Y will happen.

Think about it. I say, “X will lead to Y. Thus, X will help.”

Am I assuming that Y will happen? (“Y will happen” means there are no conditions attached to the occurrence of Y. This means that Y will happen, irrespective of X.)

No.

Am I assuming that X will make Y happen?

I don’t think so. I’m directly stating, “X will lead to Y.” How can a rephrasing of my statement be an assumption? It’s not.

From the above discussion, we understand that “Residents will reduce the amount of trash they put out for collection” is not an assumption of the above argument.

Now, let’s look at the original option A:

Residents will reduce the amount of trash they put out for collection by reducing the number of products they buy.

The option says that the residents will reduce the amount of trash in a specific way. Which way? By reducing the number of products they buy.

Does it matter to us how they reduce the amount of trash?

Not at all.

Whether they reduce the number of products or shift to using only those products that produce less trash is none of our concern.

Thus, option A is incorrect.

(B) The collection fee will not significantly affect the purchasing power of most residents, even if their households do not reduce the amount of trash they put out.

Incorrect. - This option weakens the argument; the option indicates that the collection fee may fail to reduce the amount of trash the residents put out for collection.

Since this option weakens the argument, it cannot be an assumption.

(C) The collection fee will not induce residents to dump their trash in the parklands illegally.

Correct. - This option strengthens the argument by saying that the collection fee will not lead to dumping of trash in the parklands.

On negation, the option says:

The collection fee will induce residents to dump their trash in the parklands illegally.

In this case, the argument falls flat since if the collection fee induces residents to dump their trash in the parklands illegally, charging the collection fee will not save the parklands.

Since the argument breaks down on negating the option, option C is an assumption.

(D) The beauty of county parkland is an important issue for most of the county’s residents.

Incorrect. -This option has no impact on the argument. Whether the beauty of the parkland is an important issue or not for the residents doesn’t help us evaluate whether charging the collection fee will reduce the amount of trash residents generate or not.

(E) Landfills outside the county’s borders could be used as dumping sites for the county’s trash.

Incorrect. -This option has NO IMPACT on the argument. Our concern is whether charging households a fee for the amount of trash they generate will reduce the amount of trash they generate and thus will help the parklands.

The fact that we can use landfills outside the county’s borders doesn’t impact the argument. (If the argument had been that we NEED TO reduce the amount of trash to save the parklands in the county, then this option would have weakened. Why? Because this option indicates that we don’t need to reduce the amount of trash to save the county’s parklands. We can simply use outside landfills. However, the current argument is not about what NEEDS to be done but about whether doing X will lead to Y.)