The reformer concludes that putting more people in prison cannot help to reduce crime.
Why? Because a survey of police departments shows no significant reduction in crime rate over the past 20 years yet an increase in both public expenditure and the percentage of the population in prison.
Answer choice (E) is incorrect because this is not an assumption underlying the reformer's argument. Nothing that the reformer says indicates that they take this for granted, nor does this have an impact on their argument.
Additionally, the reformer is focused on the crime rate and not the number of crimes committed.
Hope this is helpful! Please let us know if you have any further questions.