USB Debugging: PC doesn't recognize that my Moto E (2nd Gen)(Upgraded to Marshmallow) in on debugging mode So I'm trying to root my Moto E (2nd Gen) using PC apps such as Kingo Root, One Click Root etc. But the problem is that my PC doesn't recognize that my phone is in debugging mode. Moreover on my Android the following dialog box appears:

Please help me.
I have installed the Android drivers on my PC.
The USB Mobile Monitor allows you to connect your Android mobile phone
  or tablet to your PC with a simple USB Cable. All that is required is
  the download of the USB Mobile Monitor App on your device and the
  installation of the USB Mobile Monitor software on your PC.
  
  The USB Mobile Monitor allows you to replace the keyboard, mouse and
  computer screen of your PC with a single device.




Source: http://www.usbmobilemonitor.com/home.html

This is a kind of built-in system shipped with your device I guess. So,I think you need to install the APK version to get this works. It can be found here. Then follow the usage on this page.

After that, try enabling USB Debugging again.

For the rooting part, follow this guide on XDA Developers.