The best option to enhance security for the new IP cameras and scanners in this environment is C. MPSK provides for each device in the WLAN to have its own unique pre-shared key.

MPSK stands for Multi Pre-Shared Key, and it is a feature that allows different devices to connect to the same SSID with different pre-shared keys. This improves the security and scalability of the network, as each device can have its own key and role without requiring 802.1X authentication or an external policy engine. MPSK can be configured either locally on the AP or centrally on Aruba Central12.

The other options are incorrect because:

A. MPSK Local is a feature that allows the user to configure 24 PSKs per SSID locally on the device. These local PSKs would serve as an extension of the base MPSK functionality. However, MPSK Local is not suitable for this scenario, as it can only support up to 24 devices per SSID, while the client has 250 devices1.

B. Aruba ClearPass is a network access control solution that can perform 802.1X authentication and install certificates for devices. However, this option is not feasible for this scenario, as the new IP cameras and scanners do not support 802.1X authentication3.

D. MPSK Local will not allow the cameras to share a key and the scanners to share a different key. MPSK Local will assign a different key to each device, regardless of their type. Moreover, MPSK Local can only support up to 24 devices per SSID, while the client has 250 devices1.