Passage Summary: Teenagers are naturally tired early in the morning, and tired drivers are dangerous. When one town moved its school start time back by thirty minutes, teen car crashes went down, suggesting later starts make roads safer.

Conclusion: Starting the school day later than 8:00 A.M. could decrease the frequency of car accidents involving teenage drivers.

Reasoning: Teenagers are biologically prone to sleepiness before 8:00 A.M., which impairs driving, and a specific instance in Granville showed accidents decreased after the high school moved its start time to 8:30 A.M.

Analysis: The argument relies on a correlation between the time change and the accident drop to claim a causal relationship. To strengthen this, we need to bolster that causal link by eliminating alternative explanations for the decline in Granville. Look for an answer that suggests other factors—like road improvements, new traffic laws, or a general decrease in teen drivers—were not the actual cause of the safety improvement. If we can show that the accidents didn't just drop for everyone at the same time, the school-start theory looks much stronger.