问题详情

The sentence "Our planet has shrunk" underlined in Paragraph 1 means that______.
A．the earth has become physically smaller
B．the more advanced ways of traveling has made the distance between countries shorter
C．the traditional concept of our planet has become out-of-date
D．modern means of communication has made it much easier for people to communicate with each other from different parts of the world请帮忙给出正确答案和分析，谢谢！