Hardin argued that grazing land held in common (that is, open to any user) would always be used less carefully than private grazing land. Each rancher would be tempted to overuse common land because the benefits would accrue to the individual, while the costs of reduced land quality that result from overuse would be spread among all users. But a study comparing 217 million acres of common grazing land with 433 million acres of private grazing land showed that the common land was in better condition.

The answer to which of the following questions would be most useful in evaluating the significance, in relation to Hardin's claim, of the study described above?

(A) Did any of the ranchers whose land was studied use both common and private land?

(B) Did the ranchers whose land was studied tend to prefer using common land over using private land for grazing?

(C) Was the private land that was studied of comparable quality to the common land before either was used for grazing?

(D) Were the users of the common land that was studied at least as prosperous as the users of the private land?

(E) Were there any owners of herds who used only common land, and no private land, for grazing?

首先，这道题目应该如何去理解？其次，对于这个答案我也觉得百思不得其解，希望nn们能解释一下，谢谢：）

我的想法：

a study comparing 217 million acres of common grazing land with 433 million acres of private grazing land showed that the common land was in better condition.

study关注的是土地的状况：研究发现，公用土地使用后的状况比私人土地的要好。（于前面所说相反）。

首先应从“土地状况“方面入手，选项中应包含这个意思。选项A是rancher拥有的土地种类，无关。B是rancher使用土地种类的偏好，无关。D是使用者状况的比较，无关。E还是关于使用者的比较，无关。只有C是关于土地状况的比较。再进一步，比较公用和私有土地在使用后状况的好坏，前提是这两者比较前的状况一定要一致，否则没有可比性。

所以，C是正确的。

一定要看清题目问的是什么，才不会所答非所问。