Answer (D) is incorrect because it is too strong a statement. The passage tells us that following the collapse of the Quebec Bridge, the rules for engineering bridges changed and engineers started to use much more rigorous analysis. This answer choice tells us that ONLY a more rigorous analysis could have saved the Quebec Bridge from collapse. While we know that engineers decided to adopt the course of more rigorous analysis, we don't know that they couldn't have done something else to prevent the bridge from falling. For instance, maybe they could have just had more people monitoring the bridge for safety reasons.
Answer (E) is correct. The passage tells us that following the collapse of the Quebec Bridge, the rules for engineering bridges changed and they started to use much more rigorous analysis. So we know that, at the very least, the engineering rules that were used before the 1907 collapse, were not enough. Those rules led to the collapse of the Quebec Bridge so they couldn't have completely assured the safety of bridges under construction.
shunheMay 12, 2020
@mikeheath,
Thanks for the question! So we’re looking for a statement that we can properly infer from the information given to us in the passage. And the problem with (D) actually really hinges on one word: “only.” Is it really the case that only one thing, a more rigorous application of mathematical analysis to the design of the Quebec Bridge, could have prevented its collapse? Well, no. It is, of course, true that the Bridge seems to have collapsed because of the lack of rigorous mathematical application. But there may have been other methods that would’ve prevented the collapse that aren’t more rigorous applications of mathematical analysis. Here’s a rather extreme one: just have a bunch more pillars under it to support it, for example. That could reasonably prevent the collapse. And those pillars could’ve been put there with rule of thumb. The point is that “only” is an extreme word in this condition, and if you can think of any other way that the bridge’s collapse could have been prevented, (D) is wrong.
Hope this helps! Feel free to ask any other questions that you might have.
