题目选项分析

Over the past ten years, the population of Dismaston has grown five times as large as it was. During this time, the average income in the city has risen substantially, and a tremendous amount of capital has flowed into city. An independent audit found that, somewhat surprisingly, the number of violent felonies reported per year is now lower than it was ten years ago.

Each of the following statements below, if true, would explain the somewhat surprising finding EXCEPT:

【选项】During this time, the state considerably lengthened felony convicts' waiting period for parole.