Long-run profit earned by a monopolistically competitive firm is driven to the competitive level due to which factor?

a.new firms entering the market causing a shift of its demand curve

b.increased product differentiation

c.a change in the technology that the firm utilizes

d.new firms entering the market causing a shift of its supply curve

For a monopolist, how do we determine the sign of the marginal-revenue curve?

a.It is negative when the price effect is greater than the output effect.

b.It is positive when the demand effect is greater than the supply effect.

c.It is positive when the monopoly effect is greater than the competitive effect.

d.It is negative when the output effect is greater than the price effect.