Read this introductory paragraph of a persuasive essay. Which sentence states the main argument of this essay?
Why Every American Can and Must Save Energy (excerpt)

You leave the television on at night because it helps you sleep. In winter you turn up the heat, even though you could just put on a sweater.Your colleague, who lives next door, offers to carpool with you, but you decide to take your own car to work. What do all these situations have in common? Just that every day, millions of Americans make these same decisions and waste energy. Some experts have concluded that the world is going to face a peak oil crisis soon, and oil prices will rise drastically, which in turn will lead to the greatest energy crisis the world has ever faced. Given this doomsday situation, energy efficiency is the need of the hour in America today. Energy savings can be achieved by taking some simple steps that can be done by anyone.