Advertising,brand Names,packaging,and Celebrity Endorsements All Occur in Monopolistically Competitive Markets

Advertising,brand names,packaging,and celebrity endorsements all occur in monopolistically competitive markets because:

A) significant barriers to entry exist in the real world.
B) in the real world,there are very few markets with many firms.
C) that gives the producer some command over the prices of their products.
D) product differentiation seldom occurs in the real world.
E) monopolistically competitive firms have an incentive to spend as much money as possible compared to their rivals.