从下拉列表中的数据库表中打印多个字段以供选择

I currently have code which is producing a drop down with fields saved within the database table 'sueprvisor', however it is only show the variable 'E_number' when i need it to print out the corresponding supervisors 'Forename' and 'Surname' within the drop down as well? any one any idea where i am going wrong?I currently have code which is producing a drop