In the Long Run,a Competitive Firm Has a Marginal Product

Multiple Choice

In the long run,a competitive firm has a marginal product of labor,MPL = L⁻¹.The output price is $20 per unit and the wage is $7.25 per hour.The long-run labor demand curve for the firm is

A) 20 L⁻⁰.⁰⁵.
B) 7.25L⁻⁰.⁰⁵.
C) 20L⁻¹
D) 7.25L⁻¹.