Which statement is true?

A) Productivity is input per unit of output.
B) The MRP curve for the perfect competitor is steeper than the MRP curve for the imperfect competitor.
C) The firm will hire workers until the wage rate and the Marginal Physical Product (MPP) of the last worker hired are equal.
D) Relative to the U.S.economy,the Chinese economy is more labor intensive and less capital intensive.

C is incorrect because the firm will hire workers until the wage rate equals the Marginal Revenue Product (MRP) of the last worker hired, not the Marginal Physical Product (MPP). A is incorrect because productivity is defined as output per unit of input, not the other way around. B is incorrect because the MRP curve for a perfect competitor is perfectly elastic, not steeper, compared to an imperfect competitor due to the perfect competitor's inability to influence market prices. D is correct because, historically, the Chinese economy has relied more on labor-intensive methods and less on capital-intensive methods compared to the U.S. economy, reflecting differences in resource availability and economic development stages.