Diagramming

@jacaroe of course! Let's break it down . . . "Inflation rates will not stabilize unless the rate of economic growth decreases." "Unless" introduces the necessary condition and the negation of the other part of the sentence is our sufficient condition: IRS ==> REGD not REGD ==> not IRS "Yet in order to slow the economy, the full cooperation of world leaders will be required." REGD ==> FCWL not FCWL ==> not REGD Transitive property connects these as follows: IRS ==> REGD ==> FCWL not FCWL ==> not REGD ==> not IRS The conclusion here is, "Thus, it would be overly optimistic to expect stable inflation rates in the near future." The author is obviously assuming that "full cooperation of world leaders" is not realistic. Now let's take a look at (D): "If we are to produce the safest vehicles possible, we must conduct objective structural tests." PSVP ==> OST not OST ==> not PSVP "However, the performance of such objective tests will inevitably result in huge cost overruns." OST ==> HCO not HCO ==> not OST Transitive property connects these as follows: PSVP ==> OST ==> HCO not HCO ==> not OST ==> not PSVP The conclusion here is, "It is therefore unavoidable that the level of vehicle safety will not be optimal." The author is obviously assuming that the car manufacturer will not incur huge cost overruns. This is the exact same reasoning as we saw in the stimulus, so (D) would be the correct answer. Hope that helps! Please let us know if you have any other questions.