you are troubleshooting a network connection issue between the wall jack in a user's office and the switch in the communications closet. when you plug a network cable into the wall jack, there is no connection. you check the switch in the communications closet to determine if the wall jack is properly connected to the switch. unfortunately, none of the cables in the communication closet are labeled. which of the following tools should you use to determine which cable in the communications closet is connected to the wall jack in the user's office since none of the cables are properly labeled?