Self-study
Structure: Counter-Argument
The stimulus presents two arguments about government subsidies for the agricultural district of Rochelle in the country of Cariana. Alan argues that, since implementing new agricultural techniques is necessary to control the erosion of productive topsoil, and since farmers can't afford to implement these new techniques on their own, agricultural output in Rochelle will "inevitably decline" without subsidies.
Betty responds that the cause of the erosion is recurring floods, which will stop when Cariana finishes a new dam next year. She concludes that Rochelle's total agricultural output will "stabilize at the present level" even if Rochelle doesn't receive subsidies.
Analysis: Necessary Assumptions
Betty states in her premise that the cause of the erosion will be eliminated next year — so starting sometime next year, Rochelle's topsoil will no longer be eroded due to flooding. Her conclusion states that Rochelle's agricultural production will stabilize at the present level. This very specific prediction about the net effect of building the dam requires Betty to assume that between this year and next, when the dam will be completed, there will not be enough erosion of topsoil or other changes that will cause a permanent decline in Rochelle's agricultural production. Betty also assumes that the dam will be completed and not just abandoned.
11.
Which one of the following ██ ██ ██████████ ██ █████ █████████ ████████ ████████
a
Building a dam ██████ ████████████ █████ █████ ████ ███ ██████ ███ █████████ ████████ ████ ██████ ██ ███████ ██ ███████ █████ ████ █████████
Irrelevant. Betty's argument is only about Rochelle. Her argument doesn't require any assumptions about flooding in regions other than Rochelle.
b
The new farming ██████████ ████ ████ ██ ███████████ ██ ███████ ████ ███████ ██ ████████ ███ ███ ████ ██████ ██ █████ ███████ ██ ████████
Irrelevant. Alan, not Betty, is the one talking about the new farming techniques. Betty's argument isn't about those techniques, nor is it about any region other than Rochelle.
c
The current yearly ███████ ██ ████ ████ ████████████ ████ ████ ████ ██ ███████████ █████ █████ ████ ███ ███ ██ █████████ ████ ██ █████ ██ ███████ ██ ██████████ ██████ ██████ ████ ████████████ █████████ █████
Correct. Remember that Betty's argument assumes that no changes will occur between now and when the dam is finished that will permanently reduce Rochelle's output from its present level. This requires Betty to assume that if the dam puts some of Rochelle's productive land underwater, the decline in production will be counterbalanced by additional output from the remaining land.
d
The cost to ███ ██████████ ██ ███████ ██ ███████ ███ █████████████ ███ ████ ███ ██ ███████ ████ ███ █████████ ████ ██ ███████████ ███ ███████ ██ ████████ ██ ███ ██████████████ ██ ███ ███ ███████ ███████████
Irrelevant. Betty's argument isn't about the cost of anything. She isn't comparing the cost of the dam versus the subsidies. She's just saying that once the dam is finished, Rochelle's agricultural output will stabilize at its present level.
e
The government of ███████ ███ ██████████ █████████ █████████ ████ ██ █████████ ███ ██████████ ██████████████ ██ ███ ███████ ██████████ ███ ██ ███████ █ █████████████ ████
Irrelevant. Again, Betty's argument isn't about the cost of anything. It's true she assumes that the dam will be finished, and so (presumably) that the government of Cariana has enough resources to finish and operate the dam. But Betty isn't suggesting the government should both operate the dam and subsidize these new farming techniques, so (E) isn't a necessary assumption.