The Diagram Below Shows the MRP Curve for a Firm

Multiple Choice

The diagram below shows the MRP curve for a firm producing copper plumbing pipe.The factor of production being considered here is hours of labour. FIGURE 13-1
-Refer to Figure 13-1.Suppose this firm initially has the marginal revenue product curve MRP₁.One reason that the curve could shift to MRP₂ is

A) a decrease in demand for the firm's output,copper plumbing pipe.
B) an increase in the supply of labour.
C) a decrease in the wage rate.
D) a decrease in the market price of copper plumbing pipe.
E) an improvement in workers' human capital.