Which of the following statements is true about supply-side

1. The main change made by the tax laws of 1981 and 1986 was to increase marginal tax rates in order to balance the budget
2. The Laffer Curve says that, if marginal tax rates fall, tax revenues will rise, and the budget deficit will decrease
3. If the tax laws of 1981 and 1986 had had their intended effect, consumption would have risen, causing an increase in both real GDP and in the price level
4. All of these

The Laffer Curve says that , if marginal tax rates fall, tax revenues will rise, and the budget deficit will decrease.