Please answer the following question: We talk every day. When we have good news, we like to share it with our good friends and when something terrible happens, we tell it to others soon. But can you imagine that a tree can talk and share news too ? Of course, no tree moves _ and says words just as people do. Strange as it may sound, though, some trees do manage to communicate with each other. Willow trees are the best-known of these trees. When insects begin nibbling a willow tree, the tree sends out a special smell at once. This smell tells the other willows that harmful insects are coming near. All of them quickly make a chemical in their leaves. This chemical is bad to the insects. The insects do not like it and they fly away soon. In this way, the willow trees protect themselves from the insects. The next time when you take a walk in the woods, maybe the trees are "talking" to each other quietly. And when someone says that trees cannot "talk", please tell them that even trees give messages to each other, too. Willow trees send messages with _ . A) words B) movements C) smells D) sounds
A:
C