[求助]2004年1月 旧T 阅读 第19题

2004年1月
        旧T 阅读
        第19题
        答案是B

为什么不选A？A错在哪里？

thanks

19. What does the phrase "lichen colonies (line 19)suggest?

     (A) Nothing but lichens live in some locations.

     (B) Many lichens live together in one area.

     (C) Lichens displace the plants  that surround them.

     (D)Certain groups of lichens have never been separated.

附上题目，谢谢啦!!!