Which of the following commands is used to detach a mounted filesystem or storage device?

The `umount` command is specifically used in Unix-like operating systems to detach a mounted filesystem, making it safe to remove or perform other operations on the underlying storage device by removing its association with a directory.

The `mount` command is used to attach a filesystem to a specified directory, which is the opposite of detaching.

The `mkfs` command is used to build a Linux filesystem on a device, not to detach it.

The `fsck` command is used to check and repair a Linux filesystem, not to detach it.