A tough one, read carefully: You are troubleshooting a network connectivity issue for a small network. Everyone in the network is wired - no Wi-Fi allowed here. All workstations are connected to a couple of switches, which in turn are connected to a router, which is then connected to the Internet. Some people can get to the Internet just fine. Others cannot. You check every workstation and they all have an indicator light on the network card that is lit and flashes, showing some kind of activity. Finally, you log on to the faulty workstations and you cannot PING the router. You can ping the router on a good workstation. What layer of the OSI stack is likely to blame?

		The Physical Layer
		The Transport Layer
		The Application Layer
		The Network Layer