When the annual period of daylight saving time begins, and clocks are set forward one hour, many people lose an hour of sleep.
Conclusion (therefore)
Sleep deprivation is responsible for the spike in traffic accidents following daylight savings.
Evidence
The day after the clocks switch on daylight savings, there are 7% more traffic accidents than average.
Evaluate
We've got comparative evidence (7% greater) and a causal conclusion (responsible for). Those are the ingredients of an Explain Curious Fact style argument.
We can Strengthen that kind of argument by ruling out an alternate explanation for the curious fact or by increasing the plausibility of the author's hypothesis.
He's blaming the uptick in accidents on people being sleep deprived, but could there be an alternate explanation?
Maybe the reason for more accidents isn't that people are sleep deprived but that they're running late! They woke up and realized it's already an hour later than they thought, so they're already running late for wherever they need to go, and thus they're driving more aggressively than usual trying to make up time.
Goal
Look for an answer undermining the idea that the uptick in accidents is caused by people running late.
Or look for an answer making it more plausible that sleep deprivation is the culprit. We know Strengthen questions are more likely to deal with the plausibility of the author's explanation (whereas all other question types are more likely to deal with alternate explanations).