阅读理解。阅读下列四篇短文，从每小题后所给的A,B,C或D四个选项中，选出最佳选项。
Few laws are so effective that you can see results just days after they take effect.But in the nine days since the federal cigarette tax more than doubled－to $1.01 per pack－smokers have jammed telephone “quit lines” across the country seeking to kick the habit.
