MAC Address/Physical Address?

[SJ]

I know I can use System.Management library, but it returns like 6 different
values all
of which look like MAC addresses. Which one do I pick and how do I identify
it?
ManagementClass oMClass = new ManagementClass
("Win32_NetworkAdapterConfiguration");

ManagementObjectCollection colMObj = oMClass.GetInstances();

foreach(ManagementObject objMO in colMObj)

{

if(objMO["MacAddress"] != null)

MACAddress += objMO["MacAddress"].ToString();

}