During the initial cluster design，a disk heartbeat，Point-to-Point non-IP network is being planned  as part of a three-node cluster implementation. The disk environment will use LVM mirroring for disk redundancy. The volume groups will be created as Enhanced Concurrent Capable.  To facilitate disk heartbeating，how many disks per node and how many networks will be required？（）  

• A、 One disk per node，one network
• B、 Two disks per node，one network
• C、 Two disks per node，six networks
• D、 Two disks per node，three networks