There were 2 series of Cthulhu Tales, there was 1 issue in 2006 and then a series with 12 issues that started in 2008.
You have these combined into one series.
The #1A you have is the 2006 issue
#1B & #1C are the A & B covers of #1 from the 2008 series.
This one series should be split into two.
Thanks!