This question was confusing for me, so I searched the forums and came up with this topic. Let me share some thoughts about this CR:
The argument basically says: If US freezes its resource consumption at current level, resources won't be depleted so fast.
Here we have two competing answer choices (B) and (D)
(B) The United States consumes one-third of all resources used in the world.
(D) Other countries have agreed to hold their resource consumption at present levels.
I don't quite understand how does (B) help the argument. We have no info about other countries: whether they are maintaining current consumption or increasing its levels. We don't have any info whatsoever about 2/3 of world resource consumption and are basing our argument only on US (=1/3 of world resource consumption).
On the other hand, (D) states that everyone has already freezed his/hers resource consumption, except US. So if US does the same, basically in the whole world resource consumption speed will stay the same indefinitely.
I think (D) is clearly better choice...
Any further ideas/explanations would be helpful