听一段材料，回答下面几个小题。
What is the main idea of this passage?
A.How do you decide what you are going to buy in a supermarket.
B.Who decides what you should buy in a supermarket.
C.How does a supermarket make people spend more money.
Why does the food that everybody must buy spread all over the store?
A.To lead customers to all sections of the store.
B.To make it easy for customers to locate the food.
C.To provide a good service.
How much do people spend after they have been in a store for 30 minutes?
A.40 cents each minute.
B.1,500 cents in total.
C.Five dollars each minute.