An administrator is installing an ESX Host to boot from a SAN LUN. During installation, the ESX device drivers are unable to detect the HBA. Which of the following could be the issue?

A.
The HBA BIOS is not enabled

B.
The HBA is connected to a SAN using a direct connect topology

C.
The HBA is not plugged into the lowest PCI bus and slot number

D.
The HBA is connected to an active/passive storage array, but the configured port is passive

Explanation:
VMware ESX Server SAN Configuration Guide, page 61.
ESX Server Configuration Requirements for Booting from SAN

* The HBA BIOS for your QLogic HBA Fibre Channel card must be enabled and
correctly configured to access the boot LUN.
* The booting logical unit number (LUN) must be visible from the lowest numbered
HBA that has any visible LUNs.
* The boot LUN must be visible from the lowest numbered storage processor (attached to
that HBA) that has any visible LUNs.
* The boot LUN must be the lowest numbered LUN attached to that storage processor
(except for gatekeeper LUNs which are sometimes assigned LUN0).
* You must remove all internal SCSI drives for all servers.

* HBA numbers can change automatically when you add and remove PCI adapters, or
manually when you edit the /etc/vmware/devnames.conf file. The HBA must be set to the
lowest PCI bus and slot number. This enables it to be detected very quickly since the
drivers scan the HBAs in ascending PCI bus and slot numbers, regardless of the
associated virtual machine HBA number.
* If you are running an IBM eServer BladeCenter and boot from SAN, you must disable
IDE drives on the blades.