As a Result of Advertising Prices in Monopolistic Competition,are

As a result of advertising prices in monopolistic competition,are

A) higher because firms earn economic profits in the long run
B) higher because increased output leads to higher production costs per unit
C) lower if increased output allows lower average production costs per unit that more than offset the advertising costs
D) lower if advertising costs per unit fall as output increases
E) higher because advertising shifts each firm's demand curve to the right and make it flatter