WPA2

Correct Answer: Upgrade the device's wireless security to WPA2.

The best action to enhance the user's device security is to upgrade the device's wireless security to WPA2, as the question suggests. WPA2 is a stronger encryption protocol than the deprecated WPA and is more secure against various attacks, providing an added layer of security for the user's device. Disabling the SSID broadcasting, while it may make the network less visible, does not enhance the encryption level of the network, and could still leave it susceptible to attack. Similarly, enabling MAC address filtering can add an additional layer of security, but it doesn't upgrade the encryption protocol, which is the main issue here. Using an additional antivirus on the device is not specifically related to the network security concern raised in the question, and hence does not address the problem directly.

Correct Answer: Move closer to the wireless access point.

The user can improve their connection by moving closer to the wireless access point. The signal strength and connection speed of a wireless network can decline with the increasing distance and physical obstructions between the device and the wireless access point. The other solutions could potentially improve the situation, but they do not address the problem directly. Rebooting the device frequently would just be a temporary solution and might not help at all if the issue is about the signal strength. Changing the wireless channel might help in case of an interference with another device, which is not stated here. And finally, trying to connect to a different SSID could work if the actual issue was that the current network is overcrowded, but it is also not stated in the question.

Correct Answer: Wireless Intrusion Prevention System (WIPS)

The Wireless Intrusion Prevention System (WIPS) is the best tool to monitor a WPA2-protected network for possible intrusions. This system is designed to prevent unauthorized network activity and report any unusual behavior, allowing the administrator to take immediate action. The Protocol Analyzer, on the other hand, is used to monitor network traffic and capture data for analysis, but it does not function as a preventive mechanism. A VPN concentrator is used to create, control, and manage VPN connections, not to monitor wireless networks for intrusions. Lastly, the Link State Monitor is used to observe the state of network links and to report if any link state changes, not specifically suited to monitor for possible network intrusions.