请教一道OG逻辑

yibiaobiao

30. The price the government pays for standard weapons purchased from military contractors is determined by a pricing method called “historical costing.” Historical costing allows contractors to protect their profits by adding a percentage increase, based on the current rate of inflation, to the previous year’s contractual price.
Which of the following statements, if true, is the best basis for a criticism of historical costing as an economically sound pricing method for military contracts?

A. The government might continue to pay for past inefficient use of funds.
B. The rate of inflation has varied considerably over the past twenty years.
C. The contractual price will be greatly affected by the cost of materials used for the products.
D. Many taxpayers question the amount of money the government spends on military
contracts.
E. The pricing method based on historical costing might not encourage the development of innovative weapons.

个人觉得C也有道理。
材料价格greatly影响合同价格，所以按historical costing定价在经济上来说是不够sound的。
比较纠结，请高人指点，谢谢！

sdcar2010

Pay attention to the phrase "based on the current rate of inflation." If so, C supports the SOUNDNESS of the conclusion.

On the other hand, A) points out a potential long term problem of this practice. If your first step is wrong, all the following step would be ALWAYS wrong.

chenminxia1992

Learn to recognize the common flaws.
This argument exhibits a language shift.

The premise is about how the contractors protect their profits.
The conclusion is that the method used is economically sound.

The argument assumes that these two ideas are connected: that if contractors are able to protect their profits, then the method used is economically sound.

The correct answer will break the link between these two ideas: it will show that, even though the pricing method enables the contractors to protect their profits, it is NOT a method that is economically sound.

Answer choice A does just what we need: The government might continue to pay for past inefficient use of funds. Since historical costing guarantees that the contractors will make a profit, the contractors have no incentive to use government funds efficiently, resulting in a pricing method that enables the contractors to protect their profits but is NOT economically sound.