JSON Form set default value dynamicalli in select box

Hello,

I am loading dynamic values into a select box.

I am using  "IDVault.globalQuery(.......)"   to get the data and then I insert it into the select box in that way:  

instance.setFieldValue(response,"dn","Description");
Is there any way to define on the select loading that one of the options will already be selected in the select box by default?
Thank you