5. When laborers agree to have a union represent them,

a. the firm that does the hiring first negotiates with the individual laborer, then has the wage rate agreement with the laborer ratified by the union.

b. the firm that does the hiring first negotiates with the union, then has the wage rate agreement with the union ratified by the individual laborer.

c. the firm faces a horizontal supply curve of labor fixed by the union.

d. the firm faces an upward-sloping supply curve of labor as it did before, but the union, not the firm, chooses the point on the curve.

e. the demand curve for labor becomes the union’s demand.