What are two reasons that the host failed to enter maintenance mode?

An administrator creates a DRS cluster of eight ESXi 6.x hosts. There are 10 virtual machines balanced across the hosts. An attempt to place the first host into maintenance mode fails.

What are two reasons that the host failed to enter maintenance mode? (Choose two.)
A . The DRS cluster Automation Level is set to Partially Automated mode.
B . One of the virtual machines on the ESXi Host entering maintenance mode is configured with a DRS Host affinity rule Should run on hosts in group.
C . One of the virtual machines on the ESXi Host entering maintenance mode is configured with a DRS Host affinity rule Must run on hosts in group.
D . One of the virtual machines on the ESXi Host entering maintenance mode is configured with an individual Automation Level set to Partially Automated.

Answer: A,D