C1753 Multiple Choice Question

The instant I finished reading the 40th page, I heard a "ding" sound come from the device on the screen. Then, a line of words appeared on the screen:

Congratulations on reading everything in the correct order. The task is complete!

Sure enough, I noticed that there was no "Next Page" on the screen.

At the same time, the elliptical device in my hand had the same content