Which ONE of the Following Statements Is True Regarding Direct

Which ONE of the following statements is true regarding direct price-off promotions?

A) They usually produce a large immediate sales effect followed by a dip when the promotion is withdrawn.
B) They usually produce only a small immediate sales effect followed by a return to the normal rate of sales after the promotion is withdrawn.
C) They usually produce a large immediate sales effect followed by a return to the normal rate of sales after the promotion is withdrawn.
D) They usually have no effect unless the discount is larger than 10% of the normal selling price.
E) They usually have no effect unless the discount is larger than 15% of the normal selling price.