There are many root tool which can root Android system under Android 4.4, iRoot can provide a best option for you to root or unroot.
You can follow this guide:
Create a backup of all important data of the phone before following the root guide.
Ensure that the LG device is having above 80% battery.
Rooting your device will void the manufacturer’s warranty.
iRoot won’t cause any damage to the device.
Here are steps:
Step 1: Install LG driver on your computer if you have not.
Step 2. Backup your LG data and file on your computer.
Step 3: Enable USB Debugging on your LG. Go to Settings -> General -> About phone -> Software information -> tap on Build Number seven times. Again go to Settings -> Developer options and turn USB debugging on.
Step 4: Connect your phone to the PC using USB cable.
Step 5: Open and run iRoot on your PC. iRoot will detect your phone automatically
Step 6: After detecting, click “Root” on the interface.
Step 7: Now your LG has been rooted successfully. Your phone will reboot after that.