You have just added a CD.ROM drive (/dev/hdd) to your system and have added it to yourfstab. Typically you can use which of the following commands to mount media in that drive to /mnt/cdrom?

Specifying both device and mount point explicitly works for ad-hoc mounts but is redundant and error-prone when fstab already contains the entry with /dev/hdd as the device.

This is a syntax error - there is no space between 'mount' and '/dev/cdrom', making it an invalid command.

The filesystem type flag '-t cdrom' is not a valid filesystem type; the correct type for ISO 9660 CD-ROMs is 'iso9660', making this command fail.

Because /mnt/cdrom is already defined in /etc/fstab with its corresponding device (/dev/hdd), the mount command can resolve all required parameters from that file using only the mount point. This is a key feature of fstab - it allows shorthand mounting by specifying either the device or the mount point alone, and the kernel fills in the rest.

'automount' is not a standard Linux utility; the correct tools for automounting are 'autofs' or 'amd', and the syntax shown is not valid for any of them.