Consider the Usual Case Where a Higher Wage Rate Increases

Consider the usual case where a higher wage rate increases firms' marginal costs.In this case,the industry's demand curve for labor

A) is more inelastic than the individual firms' demand curves would indicate.
B) coincides with the horizontal sum of individual firms' demand curves.
C) contains only substitution effects but no scale effects.
D) is horizontal at the going market wage.