Your network is configured as shown in the following diagram. Each office contains a server that has the File Services server role installed. The servers have a shared folder named Resources. You need to plan the data availability of the Resources folder. Your plan must meet the following requirements： èIf a WAN link fails，the files in the Resources folder must be available in all of the offices. èIf a single server fails， the files in the Resources folder must be available in each of the branch offices，and the users must be able to use existing drive mappings. èYour plan must minimize network traffic over the WAN links. What should you include in your plan？（）

A. a stand-alone DFS namespace that uses DFS Replication in a full mesh topology
B. a domain-based DFS namespace that uses DFS Replication in a full mesh topology
C. a stand-alone DFS namespace that uses DFS Replication in a hub and spoke topology
D. a domain-based DFS namespace that uses DFS Replication in a hub and spoke topology