You have an Exchange Server 2003 organization. All servers have 32-bit hardware. You plan to transition to Exchange Server 2010 and deploy new Mailbox servers. You need to evaluate the current servers to provide recommendations for the deployment of the new Mailbox servers. What should you include in the evaluation？（）

A. .number of concurrent connections to Outlook Web App .number of mailbox databases.memory utilization
B. .number of concurrent connections to Outlook Web App .RPC latency.disk I/O latency
C. .number of concurrent MAPI connections.size of mailbox databases.number of mailboxes
D. .number of mailboxes.disk I/O latency.RPC latency