A and C are very close. I'm not even sure which is better. Both seem to be assumptions. Are you sure there are no typos in the answer choices? I'm not sure this is an ETS quality question
A) there are 2 ways to negate this:
negation1 = being able to take college-level courses while in prison is unlikely to deter anyone from a crime that he or she might otherwise have committed
negation2 = not being able to take college-level courses while in prison is
likely to deter anyone from a crime that he or she might otherwise have committed
If 1 is true, what would be the point of taking college-level courses if it is unlikely to deter former inmates to commit crime. If 2 is true, then it is preferable not being able to take college-level courses. A seems to be a required assumption
B) We are not interested about the rest of the population. Only prison inmates are our subject of interest
C) negation: The group of inmates who chose to take college-level courses were
already less likely than other inmates to commit crimes after being released. This directly casts some doubt in the validity of the statistics. If the inmates who took college-level courses were already less likely to commit crimes, will removing those courses have any effect at all? C needs to be assumed
D) who cares? we are not interested about high-school-level courses
E) governer's goal is not what we want to know. This is out of scope
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Best Regards,
Paul