It'll probably be the 3rd one. The key is the diameter and unfortunately I don't recall it. I'll try to remember to measure it when I get home this evening. Feel free to remind me if I forget.

You can also buy a grinder, use it for this, then return it. Not something I would normally do simply because tools usually come in handy later down the line but then again, I have had to do it in a pinch when I visited an ex gf at her dorm and she needed help hanging something heavy in her room and I didn't have a drill/bits with me. Thank you HD. <img src="/forums/images/graemlins/wink.gif" alt="" />