IP SLA allows an IT professional to collect information about network performance in real time.
Therefore it helps determine whether the QoS on the network is sufficient for IP services or not.
Cisco IOS Embedded Event Manager (EEM) is a powerful and flexible subsystem that provides real-time network event detection and onboard automation. It gives you the ability to adapt the behavior of your network devices to align with your business needs.

Link aggregation (LAG) is a partial implementation of the 802.3ad port aggregation standard. It bundles all of the controller's distribution system ports into a single 802.3ad port channel.
Restriction for Link aggregation:
- LAG requires the EtherChannel to be configured for 'mode on' on both the controller and the Catalyst switch -> Answer B is not correct.
- If the recommended load-balancing method cannot be configured on the Catalyst switch, then configure the LAG connection as a single member link or disable LAG on the controller -> Answer A is not correct while answer D is correct.
Reference: https://www.cisco.com/c/en/us/td/docs/wireless/controller/7-5/configuration-guide/b_cg75/b_cg75_chapter_0100010.html