* The issue on port 1/3 is related to speed, as indicated in the configuration output from the switch. All three ports (1/1, 1/2, and 1/3) are connected and have full duplex settings; however, port 1/3 has a significantly lower speed of 10 compared to the other two ports with a speed of 1000. This discrepancy in speed can lead to performance issues on the client PC connected to port 1/3 as it may not be able to communicate effectively with other devices on the network or may experience slow data transfer rates.
* One fundamental configuration is the speed and duplex of the interface. The speed refers to the speed of the Ethernet link. This would be a 10-megabit, 100-megabit, 1,000-megabit, or 1-gig, and a 10-gig connection. Commonly, we would also see a duplex configuration, where the duplex would be set to either half or full1.
* Many times, this configuration is set to be automatic. This means that both devices will negotiate with each other and find the best option for both speed and duplex. Some organizations prefer to manually set these. And they will configure the speed and duplex within the switch and the device configuration itself. One important consideration is that these settings need to match on both sides of the wire. So if you're configuring a device to be 1-gig and full-duplex, then the switch on the other side of the wire needs to also be configured for 1-gig and full-duplex1.
* Therefore, the correct answer is A. Speed, as it is the cause of the issue on port 1/3.
References:
* Interface Configurations - N10-008 CompTIA Network+ : 2.3