Which statement regarding workers is true?
a. An important reason why workers in developing countries earn low wages is because of limited investment in human capital.
b. Competition from low-wage nations does not cost U.S. workers their jobs.
c. Cutting off trade with countries in which workers are paid low wages improves the economic condition of these workers.
d. Living conditions in poor countries are unrelated to the degree of economic freedom and a strong and fair legal system.