2. Crimes are mainly committed by the young, and for this reason merely increasing the number of police officers or expenditures on police services has little effect on reducing the crime rate. In fact, the only factor associated with a crime-rate drop is a decrease in the number of people in the community aged fourteen to thirty. The findings above can best serve as part of an argument against (A) the likelihood that any law enforcement program will be effective in reducing the crime rate within a short time (B) increasing prison terms for young people found guilty of crimes (C) introducing compulsory military conscription for people aged seventeen to nineteen (D) raising the age at which students are permitted to leave school（A） (E) a community’s plan to increase the number of recreational and educational activities in which young adults can participate 答案为A, 我是用排除法做的, 也能得出A答案, 但是A答案是什么意思呢? 请NN看看. | 
