Which of the following are potentially valid arguments for tariffs or export subsidies, and which are not? Explain your answers.

(a) “The more oil the US imports, the higher the price of oil will be in the next world oil shortage or crisis.”

(b) “The growing exports of off-season fruit from Chile, which now accounts for 80% of the US supply of such produce as winter grapes, are contributing to sharply falling prices of these former luxury goods.”

(c) “US farm exports don’t just mean higher incomes for farmers—they mean higher income for everyone who sells goods and services to the US farm sector.”

(d) “The real price of timber has fallen 40%, and thousands of timber workers have been forced to look for other jobs.”