Which is the correct order for upgrading vSphere components?
A.
vCenter Server, ESXi hosts, VMware Tools, Virtual Machine hardware
B.
VMware Tools, Virtual Machine hardware, ESXi hosts, vCenter Server
C.
vCenter Server, Virtual Machine hardware, VMware tools, ESXi hosts
D.
ESXi hosts, vCenter Server, Virtual Machine hardware, VMware Tools
A. Nobrainer.
Source: https://docs.vmware.com/en/VMware-vSphere/6.5/com.vmware.vsphere.upgrade.doc/GUID-7AFB6672-0B0B-4902-B254-EE6AE81993B2.html