As societies develop, their members start to see things not so much according to what they need, but according to what they want. When people have enough money, these wants become demands. Now, it' s important for the managers in a company to understand what their customers want if they are going to develop effective marketing strategies  . There are various ways of doing this. One way at supermarkets, for example, is to interview customers while they're doing their shopping. They can be asked what they prefer to buy and then the results of the research can be studied. This provides information on which to base future marketing strategies. It' s also quite normal for top managers from department stores to spend a day or two each month visiting stores and mixing freely with the public, as if they were ordinary customers, to get an idea of how customers act. Another way to get information from customers is to give them something. For example, some fast food restaurants give away tickets in magazines or on the street that permit customers to get part of their meal for nothing. As well as being a good way of attracting customers into the restaurants to spend their money, it also allows the managers to get a feel for where to attract customers and which age-groups to attract. Another strategy used at some well-known parks such as Disneyland is for top managers to spend at least one day in their work, touring the park dressed as Mickey Mouse or something like that. This provides them with a perfect chance to examine the scene and watch the customers without being noticed. The main idea of the text is   _  .
how to find out customers' social needs how to develop marketing strategies how to do market research how to encourage customers to spend more money
Question: As societies develop, their members start to see things not so much according to what they need, but according to what they want. When people have enough money, these wants become demands. Now, it' s important for the managers in a company to understand what their customers want if they are going to develop effective marketing strategies  . There are various ways of doing this. One way at supermarkets, for example, is to interview customers while they're doing their shopping. They can be asked what they prefer to buy and then the results of the research can be studied. This provides information on which to base future marketing strategies. It' s also quite normal for top managers from department stores to spend a day or two each month visiting stores and mixing freely with the public, as if they were ordinary customers, to get an idea of how customers act. Another way to get information from customers is to give them something. For example, some fast food restaurants give away tickets in magazines or on the street that permit customers to get part of their meal for nothing. As well as being a good way of attracting customers into the restaurants to spend their money, it also allows the managers to get a feel for where to attract customers and which age-groups to attract. Another strategy used at some well-known parks such as Disneyland is for top managers to spend at least one day in their work, touring the park dressed as Mickey Mouse or something like that. This provides them with a perfect chance to examine the scene and watch the customers without being noticed. The main idea of the text is   _  .
A. how to find out customers' social needs
B. how to develop marketing strategies
C. how to do market research
D. how to encourage customers to spend more money
Answer: