thanks for the kind words. (Althouh noone would call me an "angel" let alone a "God"!)
By "insufficient" you seem to mean that choice B does not guarantee that the US' cutting consumption will save the world from resource-depeletion (other countries also must cooperate, you point out). Then, you are correct in pointing out that choice B is "insufficient". But the author is not making that argument. He is not arguing that the US' cutting consumption will save the world from resource-depletion.I AGREE that B is better than D....but B alone is insufficient, that's all....
Even if the US is a significant consumer, both the US and the rest of the world MUST complement each other to reduce overall consumption... basically B+D is my answer....In Data Sufficiency language C
Instead, the argument is less bold and much more simple than that. The author is just arguing that it is imperative (it is a "must") that the US stabilize its consumption. And that's it--there's nothing more to the argument. If Choice B is true, then it does indeed become more imperative (more of a "must") for US to do so. Thus choice B does strengthen the argument.
If anything, choice D actually slightly weakens the argument: After we learn that other countries have agreed to stabilize their own consumption, it is now (relatively) less of a "must" for the US to do so.
