Which statements concerning the event model of the AWT are true？（）
- AAt most one listener of each type can be registered with a component.
- BMouse motion listeners can be registered on a List instance.
- CThere exists a class named ContainerEvent in package java.awt.event.
- DThere exists a class named MouseMotionEvent in package java.awt.event.
- EThere exists a class named ActionAdapter in package java.awt.event.