Which of the Following, If Happens, May Result in an Increase

Multiple Choice

Which of the following, if happens, may result in an increase in the relative price of primary products in the world market?

A) The marginal cost of producing the primary goods declines over time
B) Productivity growth in the primary sectors is slower than that in the manufacturing sectors
C) The demand for primary products declines over time
D) The stock of inventories of primary products unexpectedly increases