Nice Question - a typical GMAT type !
The statement never says anything that ppl are using these non-prescription drugs to commit suicide. In fact, it clearly says that overdose cases have doubled. I think the second half is meant to confuse the reader. It is simply giving a status of proportion of elderly and teenagers.
I narrowed down to A & D. Read the question again and realized that it is asking about the assumption we need to make to justify that suicide rate is increasing. An increase, double, in overdose case can only be relevant to an increase in suicide rate if this overdose was not accidental. Else, they are accidental deaths.Elderly suicide has jumped 70% but nothing relates it to the pills
The elderly suffered the greatest number of overdoses from the non-prescription sleeping pills.Irrelevant
Overdosing on sleeping pills was not the most pervasive method of suicide in Travonia ten years ago.Very obviously irrelevant
The number of deaths from natural causes in Travonia has decreased in recent years.An increase, double, in overdose case can only be relevant to an increase in suicide rate if this overdose was not accidental.
The majority of deaths resulting from overdosing on non-prescription sleeping pills were not accidental.Irrelevant
Travonia's suicide rate is higher than the worldwide average suicide rate.
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