How to get array of int as json result in mvc 4?

This is my json code.

public JsonResult GetCheckedPerm(int usr_groupId)
{   
    List<int> selectedradio = GrpPermBAL.GetData(usr_groupId);        
    return(selectedradio,JsonRequestBehavior.AllowGet);
}

This is my code to get data

public List<int> GetData(int groupId)
{
    return db.ts_grp_perm_mapping
             .Where(c => c.grp_id == groupId)
             .Select(c => c.perm_id)
             .ToList();
}

Here using above code I am returning array of int. But I am not able to result aray of int in json. I am getting below error cannot convert lambda expression type System.Web.Mvc.JsonResult because it is not a delegate type.