Which command would add redundancy to the pool1 storage pool?

Your server has a ZFS storage pool that is configured as follows:

The server has two spate 140-GB disk drives: c3t5d0 c3t6d0
Which command would add redundancy to the pool1 storage pool?

A.
zpool attach pool1 c3t5d0 c3t6d0

B.
zpool attach pool1 c3t3d0 c3c5d0; zpoo1 attach pool1 c3t4d0 c3t6d0

C.
zpool mirror pool1 c3t5d0 c3t6d0

D.
zpool add pool1 mirror c3t5d0 c3t6d0

E.
zpool add raidz pool1 c3t5d0 c3t6d0

Explanation:
You can convert a non-redundant storage pool into a redundant storage pool by
using the zpool attach command.
Note: zpool attach [-f] pool device new_device
Attaches new_device to an existing zpool device. The existing
device cannot be part of a raidz configuration. If device is not
currently part of a mirrored configuration, device automatically
transforms into a two-way mirror of device and new_device. If
device is part of a two-way mirror, attaching new_device creates a
three-way mirror, and so on. In either case, new_device begins to
resilver immediately.
Reference: Converting a Non-Redundant ZFS Storage Pool to a Mirrored ZFS Storage Pool
Reference: man zpool