The United States has many different kinds of climates. On the west coast the temperature changes very little between summer and winter, but the north central states have a very different kind of climate. In those states, people wear light clothing during the summer, and they need heavy wool or fur clothing in the winter.In the eastern part of the United States, summer temperatures are very different from winter temperatures. Summers are usually hot, winters are usually cold. Spring temperatures are comfortably warm, and autumn temperatures are pleasantly cool.Years ago, people in the cold parts of the United States didn’t often get fresh vegetables and fruits during the winter. Today, however, trucks and trains deliver fruit and vegetables very efficiently to all parts of the United States. In this way, Americans "send their climates" to people in other states.（）

A. The climate varies a little all over the United States.
B. The climate varies a lot in the United States.
C. There is no variation in climate in the United States.
D. The climate is very pleasant all the year round.