Nowadays we can see more and more electric bikes in the street. Electric bikes are easy to1. They run fast and make no pollution. So they become very2in many big cities in China.But the electric bikes also cause more traffic accidents. So China plans to make a new rule3the electric bike riders. If an electric bike is heavier than 40 kilos and can go faster than 20 kilometers an hour, its rider must get a license(许可证). It means riders have to pass driving tests4they ride their electric bikes on the road.

    People have different ideas about the plan. Some welcome the plan because they think it will make the street much safer. But some are not happy with the new rules at all. One rider said, “I don't want to get a license or anything. That's too much5.” What's your idea?

如图，点A是直线l外一点，在l上取两点B，C，分别以A，C为圆心，BC，AB长为半径画弧，两弧交于点D，分别连接AB、AD、CD，则四边形ABCD一定是（　　）

​