A systems administrator needs to extend the logical volume /dev/mapper/linux-root to use all available space in its volume group. The filesystem should be extended as well. Which of the following…

`lvm pvresize` is used to resize physical volumes, not logical volumes, and the `-l100%` option used here is not standard for `pvresize` to refer to free space.

`lvchange` is used to change logical volume parameters like activation status or permissions, but not to extend its size using available free space.

`lvextend -l+100% /dev/mapper/linux-root` would attempt to extend the logical volume by 100% of its current size, not 100% of the free space in the volume group, and also lacks the `-r` option to resize the filesystem.

The `lvresize` command is used to resize logical volumes, and the `-l 100%FREE` option extends the LV to use all unallocated physical extents in the volume group. The `-r` option automatically resizes the filesystem on the logical volume after the LV itself has been extended, which is crucial for the space to be usable.