A、Place all user mailboxes on back-end servers. Deploy Outlook Web Access on three front-end servers that are members of the Network Load Balancing cluster

B、Place all user mailboxes on back-end servers that are members of a Network Load Balancing cluster. Deploy Outlook Web Access on the back-end servers

C、Place mailboxes for remote users on one back-end server and place all mailboxes for main office users on another back-end server. Deploy Outlook Web Access on the back-end server that contains the mailboxes for remote users

D、Place all user mailboxes on two back-end servers that are members of a Network Load Balancing cluster. Place mailboxes for remote users and mailboxes for main office users into separate storage groups. Deploy Outlook Web Access on three front-end servers. Configure the front-end servers to access only the back-end Network Load Balancing cluster