Why do college graduates earn more in wages than workers with only a high school diploma?

If relative purchasing power between the United States and Argentina is 3.22 pesos per dollar, under which circumstances would we say that the dollar is "overvalued"?

A) if the actual exchange rate between the dollar and the Argentinean peso is 3 pesos per dollar B) if the actual exchange rate between the dollar and the Argentinean peso is 4 pesos per dollar C) if the actual exchange rate between the dollar and the Argentinean peso is 3.22 pesos per dollar D) if the actual exchange rate between the dollar and the Argentinean peso is 0.22 pesos per dollar

If total utility increases at a decreasing rate as a consumer consumes more coffee, then marginal utility must

A) decrease. B) remains constant. C) be negative. D) increase also.