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

In the short run,a competitive firm has a marginal product of labor,MPL = 5L⁻⁰.⁵.The output price is $10 per unit and the wage is $7 per hour.The short-run labor demand curve for the firm is

A) 5L⁻⁰.⁵.
B) 15L⁻⁰.⁵.
C) 35L⁻⁰.⁵.
D) 50L⁻⁰.⁵.