If the Wage Rate in a Purely Competitive Labor Market

If the wage rate in a purely competitive labor market increases, it will cause the

A) marginal resource cost curve for a single competitive firm in the industry to shift down.
B) marginal resource cost curve for a single competitive firm in the industry to shift up.
C) labor supply curve for a single competitive firm to shift downward.
D) labor supply curve for the industry to shift rightward.