This is a strengthen question type as well as a cause-effect question. It is important to understand some of the assumptions that the person making a cause-and-effect argument makes. The speaker believes that the named cause is the only thing that produces the effect. Understanding this assumption is key to eliminating wrong answer choices as well as matching the right one.
Therefore, to support the adduced cause-and-effect argument, we have the following options:
* Show that the effect does not happen when the cause does not happen or vice versa (which is essentially the same thing, anyway)
* Show that effect is not caused an alternative cause.
* Show that the reverse is not true, i.e. the attributed cause itself is not actually an effect caused by the supposed effect
* Show that the two events are not a mere correlation
* Show that a third event does not cause the two events to happen
* Show that the data/sample used in making the cause-and-effect assertion is valid (not flawed or unrepresentative of the broader claim)
Back to the question: The conclusion essentially says that improved car safety caused average age to increase. How do we support this claim? Well, by finding an answer choice that does any (or a combination of the above listed items).
Option B bolsters the argument by defending the argument against any claim that the increase in average driver age was caused by a reduction in the frequency of accidents. In other words, to support the argument that car safety measures had increased the average age of drivers, option B rules out the possibility that that increase may have been brought by a reduction in the frequency of accidents between 1965 and 1980.
If you were tempted to choose answer A, read more closely and you will realize that it actually weakens (not support) the argument, because it is essentially saying that older drivers are less frequently involved in accidents (compared to younger drivers), resulting in an increase in driver age since many more younger drivers may be dying from accidents than the older ones are. Hope this helps.
Kudos, if you find this insightful.
Der alte Fritz
+1 Kudos me - I'm half Irish, half Prussian.