【已刪除】46. What is the main idea of this passage?
(A) Retailers tend to spend a lot of money doing research on the layout of the stores.
(B) Retailers use a lot of measures based on physical and psychological stu dies to increase their profit.
(C) Shoppers must be careful when they decide to buy anything with a price tag which ends with a 9.
(D) Retailers know that consumers will pay much more attention to the dolla rs than the cents.