Hi Belkis,
I think you have selected a hardware platform that only allows AD1 to be output. For example on the PurePath Wireless Audio EB the input on the onboard AIC3101 is connected to AD1, and this is the reason for only allowing this ADx to be output. If you select hardware platform: Custom design you can select AD0, 1 and 2 for whatever you want.
Best regards
Kristoffer