What visual indicator shows that the device is recording a video?

The correct choice indicates that a red dot with a timer located in the corner serves as the visual indicator that the device is recording a video. This specific visual cue is widely used in various video recording devices, as it provides clear and immediate feedback to the user that recording is in progress. The red dot is often synonymous with "record" in many contexts, making it instantly recognizable.

The addition of a timer provides further context, showing not only that recording is active but also how long the recording has been ongoing. This helps users manage their recording duration and ensures important events are captured accurately.

In contrast, the other options do not ensure clarity about the recording status. A flashing blue light on the screen might imply connectivity or another status rather than recording. A steady green light might suggest the device is powered on or in standby mode, but not necessarily recording. Similarly, a notification sound may be missed in noisy environments, whereas a visual indicator is always present for the user to see at a glance.