SystemA has a file system named /library that contains a library of files to be shared to the entire company. Each remote system has read-only access to this file system through the /library mount point.
Occasionally, serverA goes down for maintenance and users can no longer access the data in the library. Therefore, you have configured a second server, named systemB, that users can access when systemA goes down. They access the systemB server through the /library2 mount point. However, when systemA goes down, all the users need to be instructed that they are to use /library2 temporarily until systemA comes back up. Which answer describes a solution to this problem?

A.
Mount the file systems as follows:mount -F nfs systemA:/library,systemB:/library /library

B.
Mount the file systems as follows:mount -F nfs -o ro systemA:/library,systemB:/library /library

C.
Mount the file systems as follows:mount -F -o ro nfs systemA:/library systemB:/library /library

D.
Use AutoFS to maintain both mountpoints and have the users access either /net/systemA/library or /net/system/library