G.729 A or B or both-which does astersik have available

Hi all
I have a question and hope it has not been answered before and I apologize if it has. I have searched the forums and mail but have not seen this answered conclusively.
Does the G729 codec and licenses which digium sales or which ever one asterisk uses, an g729 a or b or both; I have had a hard time getting a conclusive answer.
If it does use g729b how could I show evidence to a client that it is b and not a?
This is huge, I could possibly turn a long time avaya user to asterisk if I can show the use of g729 b; bandwidth usage being the issue.
Thanks a bunch appreciate any help or being pointed in the right direction. :confused: