A customer would like to add a second HMC to an environment which consists of multiple POWER7 and
POWER8 systems.
Which of the following is a requirement for both HMCs to be able to manage all the systems?

A.
Both HMCs must be on the same HMC VLAN.

B.
Each HMC must be on a dedicated HMC VLAN.

C.
All the POWER7 systems must be at the same firmware level.

D.
Both HMCs must be at the same version of HMC Code.

Explanation:
HMC Version 8 can be used for POWER8, POWER7, and POWER6 based servers.
HMC Version 7 can used for POWER7, POWER6 and POWER5 based servers.
https://www-304.ibm.com/support/customercare/sas/f/hmcl/home.html