6-Wire Thermostat Install Question? Renters ripped the thermostat off the wall and took it! There...

Renters ripped the thermostat off the wall and took it! There are 6-wires comming out of the wall, they are:
W-white
Y-yellow
G-green
R-red
B-blue
Gr-grey
the white and gray wires look to be connected side by side next to only the ends anyone seperated, while the other wires are all single wires comming out of the wall. Any suggestion on installing and buying a thermostat would be helpful...gratitude
My gas furnace keep going out?
Answers:    buy yourself a programmable thermostat. it comes with the installation instructions.(very confident!) it also helps you set the time you want solid temps to be. a great money savor too!
How to carry dry concrete out of a...
Look at the markings on the new thermostat, it will show what color go where... R for Red, W for White, etc. Also the instructions for installing the fresh thermostat will point you in the right directon.