Which of the following commands will allow an administrator to adjust the number of mounts after which an existing filesystem will be checked by e2fsck?

`debugfs` is an interactive filesystem debugger used for low-level examination and modification of filesystem structures, not for setting `e2fsck` check intervals.

`dumpe2fs` displays information about an ext2/ext3/ext4 filesystem, including its current `e2fsck` settings, but it does not modify them.

`mode2fs` is not a standard Linux command used for adjusting filesystem parameters.

The `tune2fs` command is specifically designed to modify adjustable parameters of existing ext2/ext3/ext4 filesystems. It can be used with the `-c` option to set the maximum number of times the filesystem can be mounted before `e2fsck` automatically checks it.

`mke2fs` is used to create a new ext2/ext3/ext4 filesystem and can set initial parameters, but it cannot modify parameters of an already *existing* filesystem.