Replacing old round Honeywell with ecobee thermostat - won't power up

So the C wire isn't connected to anything in the attic, and there is no terminal block with a place to hook it up.

This is what I have:




Where do I hook up the C wire?

It's the ecobee3 lite, and it did come with the extender. From what I understand, though, the purpose of the extender is just to avoid having to run wire through the wall if you don't have a C wire. I have a C wire already in the wall, it's just not hooked up on either end. The extender has the same 5 wires that I already have, so there is the same problem. Which terminal in the photo does the C wire on the extender go?

Yeah it seems so. I couldn't make out the letter, but I checked voltage and hooked it up. Seems good!