Why is the OpenBoot prompt not available?

You are trying to reach the OpenBoot prompt (ok) from Oracle Solaris on a SPARC T4-1 system
running Oracle VM Server for SPARC. The OpenBoot firmware is not available. Why is the
OpenBoot prompt not available?

A.
It has been removed from memory.

B.
It was not installed on the system.

C.
The service processor property “auto-boot” is disabled.

D.
An incorrect version of OpenBoot firmware is installed.