Sales Promotion Expenditures Increased as a Percentage of Budget Expenditure

Sales promotion expenditures increased as a percentage of budget expenditure for a number of years. Growth has, however, recently slowed. Which of the following is a factor that has contributed to the growth of sales promotion expenditures?

A) Many brands have come to be seen as dissimilar.
B) The efficiency of advertising as a promotion has improved.
C) The trade demands more deals from manufacturers.
D) Consumers have become less price-oriented.
E) The number of brands in the market has decreased.