7. The postal service is badly mismanaged. Forty years ago, first-class letter delivery cost only three cents. Since then, the price has increased nearly tenfold, with an actual decrease in the speed and reliability of service.

Each of the following statements, if true, would tend to weaken the argument above EXCEPT:

(A) The volume of mail handled by the postal service has increased dramatically over the last forty years.

(B) Unprecedented increases in the cost of fuel for trucks and planes have put severe upward pressures on postal delivery costs.

(C) Private delivery services usually charge more than does the postal service for comparable delivery charges.

(D) The average delivery time for a first-class letter four decades ago was actually slightly longer than it is today.（E）

(E) The average level of consumer prices overall has increased more than 300 percent over the last forty years.

我选c, c是明显的无关项。

答案为E。

C说私人的可比服务更贵，说明邮政服务涨10倍不算贵，价格低点，可靠性当然差点，不是管理的问题。涨价支持结论受削弱。

E说价格指数才涨3倍多。而邮政服务却涨近10倍，还是贵了，而服务的可靠性和速度却减少。所以还是管理问题。支持结论。

彻悟，谢谢！！