[求助]pp1阅读中,一句话的理解?在线等!

Only 20 percent lived in towns

and cities of 2,500 or more, the census definition of

an urban area after 1880.

按我理解,20% of 2500 or more  live in towns and cities.也就是 500,但答案是2500?

57. According to the passage, which

   of the following was the census

   definition of an urban area after

   1880 ?

   An area with a population that

      had recently increased by

      20 percent  

   A city with a population of

      1 million or more people  

   A town or city with a population

      of at least 2,500  

   An area or region with a

      population of at least 100,000