The question now is why is WINDOWS Explorer using data ? Windows Explorer is a file manager.
Click on the top line in the right pane: The one marked as Windows Explorer in your screenshot.
I would like to see what info comes up in the pop up box:
What is going here is that a part of Windows (Windows Explorer, not to be confused with the program Internet Explorer) is accessing the internet and using large amounts of data.
This could be the result of improper "associations" being set. It could also be the result of virus or malware activity.
I would like to see the IP address of where it is connecting to.
That will be in that pop up box.