A customer plans to consolidate several systems onto POWER7. Their immediate requirement is to have a single Power 770, and they will buy a second Power 770 at a later stage. They want to keep their existing three POWER5 570s and three POWER6 520s which are all managed by an HMC (7310-CR3). Which of these statements is true and would minimize the cost?（）

A.All the machines can be connected to the existing HMC, as long as it is updated to code level 7.7.1 or later

B.The Power 770 requires an HMC (7042-CR5 or later), so they must buy one. All of the systems can be managed by this new HMC

C.They should buy a new HMC for the Power 770 system, and leave the POWER5 and POWER6 based  systems connected to the existing one

D.The Power 770 requires an HMC, so they should connect the Power 770 to the HMC and convert the POWER5 and POWER6 based servers to IVM