Food is very important to our health. Everyone needs to eat well if he or she wants to have a strong body.
Our minds, like our bodies, always need the best food. This kind of food is knowledge. We start getting knowledge when we are very young.

A．把开关S接b点，调节电阻箱，使电流表的示数为I；

B．读出电阻箱的示数R₁；

C．把开关S接a点，读出电流表的示数为I；

D．根据电路图，连接实物，将电阻箱的阻值调至最大．

如图所示的四种情景中，属于光的反射的是（　　）