Building a lookup table with 3 variables/3 answers

Hi I'm a new user of excel 2007 with basic skills.
I'm trying to figure out how best to build a table to do:

IF A1="yes", "no", "na" and
IF B1="yes", "no","na" and
IF C1="yes","no","na" then
"AT" or "IC" or "VE"

So, I need a table that can look up responses to three questions, then lookup the corresponding answer (AT, IC or VE). Some of the combinations of anwers will yield the same anwer (i.e: yes, yes, yes=AT and yes,yes,no=also AT). I'm trying to come up with the most probable answer by evaluating these three questions; Thus; 10 combinations will yield an answer of "AT", 10 combo will yield "IC" and 7 combo will yield "VE"

I've done this with 2 variables, but can't seem to get it to work with three...

Thanks and looking forward to any assistance & advice.