During an internal IT organization planning session， it is decided that a new cluster node would  Enhance the performance of a distributed corporate application. Planning details have been assigned to the administrator. System outages are limited to one weekend per month； therefore， availability will be a key issue in the planning process.  How much cluster downtime will need to be allocated for adding a new node？（）  

• A、 None，everything can be done with the cluster active.
• B、 Minimal downtime will be required to import the volume groups.
• C、 Several hours are required for testing before final synchronization.
• D、 Minimal downtime will be required to connect and test the serial network.