British society is considered to be divided into three main groups of classes--the Upper Class, the Middle Class, and the Lower or Working Class. This is known as the Class system and it is important to know something about it if you want to understand British people and society. Most British people grow up with a deep knowledge and understanding of the class system even if they are not very conscious of it. Most people know which class they belong to by the way they speak, their clothes, their interests or even the type of food they eat. Social class is not only about behavior and attitudes. For example, although many upper class people are rich and may own a lot of land, having a lot of money does not make a person upper class. It is also important to come from a particular kind of family, have friends who are considered suitable, have been to a certain type of private school and speak with the right kind of accent. There are people who are poor but who do not think of themselves as working class, because their family background, education, political opinions, etc. are different from those of most working-class people. Many people do not like the class system but it is impossible to pretend that these differences do not exist or that British people do not sometimes form opinions in this way. According to the passage, the idea of the class system in Britain   _  .
exists only in the mind of  foreigners is deeply rooted in the British people is now under severe attack is regarded as a long system