What are two likely reasons for this issue?

An administrator is unable to remove an ESXi 6.x host from a vSphere Distributed Switch.

What are two likely reasons for this issue? (Choose two.)
A . Vmkernel interfaces on the switch are still in use.
B . VM Network port group adapters are connected to different switch.
C . Physical NICs are migrated to different switch.
D . VM Network adapters are connected to this switch.

Answer: A,D