A、It has a cathedral. B、It has a population of 4,000. C、It has a large population. D、It has a city hall C题目问为什么Birmingham专门成为一个城

As city residents, we all think that we know what the word "city" means, but do we really (32) ? Here are some interesting facts.
    In Britain, a town of any size can be called a city, if it has a cathedral. So London today includes the two cities of London and Westminster, because both parts have a cathedral (33) . But a small place in North Wales called St. Asaph has a population of fewer than 4,000 and yet because it has a cathedral it is also called a city. on the other hand, Birmingham was so large that it was specially made into a city, even though it did not have a cathedral (34) .
    In the USA, "city" is simply a legal term, and it does not depend on the size or importance of the place. Confusingly, however, the US Census Bureau, an American government department that conducts official counts of the population, classifies any place with a population of over 2,500 as a city, no matter how far out in the countryside it is.
    The world’s most densely populated city is the area of Japan that includes Tokyo and Yokohama, which has an estimated 29,272,000 inhabitants (34) . But, in the future, it may well be replaced by a city in China or a city in India.
    So, what is a city? It all depends on where you live.