Company.com has a p5-570 with an application running on each of three Micro-Partitions. The disk I/O is shared through a VIO server. A technical specialist has been asked to upgrade the VIO server. Which of the following procedures should be taken to maintain the integrity of the partitions？（）

A. Shut down all client partitions before updating the VIO server.
B. Disconnect the client partitions from any IP networks before updating the VIO server.
C. Update the client partitions to the latest OS maintenance level before updating the VIO Server.
D. Update the VIO server while the partitions are running， but reboot each client partition at a convenient time after the update.