Which command creates a new SyncMirror aggregate, letting Data ONTAP select the disk drives?

A.
aggr create aggrX -d 12

B.
aggr create aggrX -m 12

C.
aggr mirror aggrX -m 12

D.
aggr mirror aggrX -n 12

Explanation:
https://library.netapp.com/ecmdocs/ECMP1196890/html/man1/na_aggr.1.html
The following commands are available in the aggr suite:

If you use the -d disk1 [ disk2 … ] argument, the node creates the aggregate with the specified
spare disksdisk1, disk2, and so on. You can specify a space-separated list of disk names. Two
separate lists must bespecified if the new aggregate is mirrored. In the case that the new
aggregate is mirrored, the indicated disksmust result in an equal number of disks on each new
plex.
The disks in a plex are not permitted to span spare pools. This behavior can be overridden with
the -f option.
The same option can also be used to force using disks that do not have matching rotational speed.
The–foption has effect only when used with the -d option specifying disks to use.
The -m option can be used to specify that the new aggregate be mirrored (have two plexes) upon
creation. Ifthis option is given, then the indicated disks will be split across the two plexes. By
default, the new aggregatewill not be mirrored.
aggr mirror aggrname
The -n option can be used to display the command that the system will execute without actually
making anychanges. This is useful for displaying the automatically selected disks, for example.