Recall the discussion about the demand for oil in your textbook. Which of the following correctly explains why the demand curve for oil is negatively sloped? As the price of oil rises:
1) The quantity demanded of oil decreases due to substitution effect.
2) The quantity demanded of oil decreases due to income effect.
3) The quantity demanded of oil decreases due to law of demand.
4) The quantity demanded of oil decreases due to increase in supply.