In regards to total surplus, which statement is true? a. There is always too little entry in monopolistic competition, due to barriers to entry. b. There is always too little entry in monopolistic competition due to the product variety effect. c. There is always too little entry in a monopolistically competitive industry due to the business-stealing effect. d. There is always too much entry in a monopolistically competitive industry, as in the long run firm produce more than the quantity that will minimise average total costs of production. e. None of the above