An administrator has recently upgraded their Update manager infrastructure to vSphere 5. Several hosts and virtual machines have not been upgraded yet. Which vSphere object cannot be upgraded by Update Manager when running against a legacy host?

A.
Virtual Machine Hardware

B.
ESX Host

C.
ESX Patches

D.
VMware Tools

Explanation:

Page 144 from vsphere-esxi-vcenter-server-50-upgrade-guide.pdf and page 86 from vsphere-esxi-vcenter-server-50-virtual-machine-admin-guide.pdf

Table 7-1. ESXi Hosts and Compatible Virtual Machine Hardware Versions