In the figure given below, we see an expansion of the production-possibility curve (from PPC 1 to PPC 2 ). The two goods produced are wheat and cloth, which are land-intensive and labor-intensive respectively. T he outward shift of the production -possibility curve is likely the result of: Cloth PPC 2 PPC 1 0 a. a fall in average cost of producing cloth . b. an increase in the price of cloth. c. an increase in the size of the labor force , the area under cultivation remaining unchanged . d. an increase in the national amount of usable land , the size of the labor force remaining unchanged .