-If Perfectly Competitive Lawn-Care Firms Are Making an Economic Profit

-If perfectly competitive lawn-care firms are making an economic profit, then

A) they are not equating marginal revenue to marginal cost.
B) government regulation will be imposed to decrease their profit.
C) the firms must be superior and will continue to make an economic profit.
D) wages will be bid up until the economic profits are gone.
E) new firms will enter the industry.