Which hardware storage option, when set up with redundant disks, offers the least stability, availability, and reliability for Mysql data?

D is correct Because:
If reliability is a consideration for your data, do not configure InnoDB to use data files or log files on NFS volumes.
Potential problems vary according to OS and version of NFS, and include such issues as lack of protection from conflicting writes, and limitations on maximum file sizes.

Even when the preceding precautions are observed, this kind of setup works only with MyISAM and MERGE tables, and not with any of the other storage engines.
Also, this warning against sharing a data directory among servers always applies in an NFS environment.
Permitting multiple MySQL servers to access a common data directory over NFS is a very bad idea.
The primary problem is that NFS is the speed bottleneck. It is not meant for such use.
Another risk with NFS is that you must devise a way to ensure that two or more servers do not interfere with each other.
Usually NFS file locking is handled by the lockd daemon, but at the moment there is no platform that performs locking 100% reliably in every situation.

It is not a good idea to configure InnoDB to use data files or log files on NFS volumes. Otherwise, the files might be locked by other processes and become unavailable for use by MySQL.

Do not put MySQL tables on an NFS-mounted volume.
NFS uses a message-passing protocol to write to files, which could cause data inconsistency if network messages are lost or received out of order.