Good question to use for practice with zooming in on the exact scope of the conclusion.

Country B’s goal is to REDUCE DEPENDENCE ON FOREIGN OIL. The way it plans to do this is by requiring cars to run on ethanol as well as gas. With topics such as this one, which are often in the news, it’s tempting to bring in a whole string of assumptions that we know from the real world, but be vigiliant! You can only use the information that you have in the argument.

(A) Whether something else is superior does not affect whether ethanol would or would not help reduce the amount of gasoline (and therefore imported oil) needed. Eliminate.

(B) The relative rates of production of each material don’t matter—and we already know that we have a domestic oil deficit, bc we have to import oil! Eliminate.

(C) Whether Ethanol can be used in other ways doesn’t matter—we just want to help support the claim that mandating ethanol in cars will reduce foreign oil dependence. “Reduce” is a very clear-cut term—if we reduced the imported oil by one drop, that would still count. So while using ethanol for many other things might help with the scale of imported fuel reduced, that scale does not matter…we just want to help prove we would need at least one drop less. Eliminate.

(D) Any time you see a “not” thrown in there, it can make it harder to figure out what the thought really is. That is a deliberate move on the part of the test-writers. Having already eliminated A-C, this would be a safe place to use the negation test, to help unravel the meaning of this choice(do NOT use this test on every answer choice, as it will take way too long).

If gas consumption IS increasing at a substantially higher rate than domestic oil and ethanol production, that means that we would need more gas (and that gas would need to come from imported oil). If that is the case, then even mandating ethanol use in cars would not be sufficient to meet this substantial increased need, and therefore foreign oil dependence would NOT decrease. This is likely our answer.

(E) The relative efficiency of ethanol versus gas doesn’t matter—we care about reducing oil dependence. This is a “helpful” assumption, but not a necessary one. It’s great that ethanol is as efficient as gas (and by extension, that we could replace gas with ethanol in a one-to-one ratio) but even if it were only half as efficient, we could still produce 2x the amount of ethanol and reach our goal of reducing foreign oil dependence. Eliminate.

Country B's oil production is not sufficient to meet its domestic demand. In order to sharply reduce its dependence on foreign sources of oil, Country B recently embarked on a program requiring all of its automobiles to run on ethanol in addition to gasoline. Combined with its oil production, Country B produces enough ethanol from agricultural by-products to meet its current demand for energy.

Type - Assumption
Boil it down - Combined with its oil production, Country B produces enough ethanol from agricultural by-products to meet its current demand for energy.

A. Electric power is not a superior alternative to ethanol in supplementing automobile gasoline consumption. - Out of scope

B. In Country B, domestic production of ethanol is increasing more quickly than domestic oil production. -Irrelevant- as long as B can use both of them to meet domestic demand all is well .

C. Ethanol is suitable for the heating of homes and other applications aside from automobiles. - Irrelevant

D. In Country B, gasoline consumption is not increasing at a substantially higher rate than domestic oil and ethanol production.- Correct - on negation this breaks the argument . If rate of gasoline consumption is substantially higher than domestic oil and ethanol production , then the conclusion will fall apart .

E. Ethanol is as efficient as gasoline in terms of mileage per gallon when used as fuel for automobiles. Irrelevant - Efficiency is not our concern

Answer D
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