On a Linux system, which of the following is a valid command format for mounting a CD-ROM so that its ISO 9660 filesystem is accessible at /mnt/cdrom?

Introduction / Context:
Mounting a CD-ROM (or DVD) on Linux requires specifying both a block device and a mount point. The command may optionally include a filesystem type (ISO 9660 or UDF). This question checks your ability to recognize a syntactically correct mount invocation and to spot common mistakes such as missing arguments or malformed paths.

Given Data / Assumptions:

• Device path is typically /dev/cdrom or /dev/sr0.
• Mount point directory exists, commonly /mnt/cdrom or /media/cdrom.
• The CD uses the ISO 9660 standard (or UDF); either can be auto-detected on modern systems.

Concept / Approach:
A correct manual mount includes two positional arguments: the device and the mount point. The general form is: mount -t iso9660 /dev/cdrom /mnt/cdrom or simply mount /dev/cdrom /mnt/cdrom if the kernel auto-detects the type. None of the provided options exactly match valid syntax: one contains an erroneous space in the path, and the other two omit required arguments.

Step-by-Step Solution:

Verification / Alternative check:
Run 'mount | grep cdrom' to confirm the device is mounted. Use 'df -T /mnt/cdrom' to verify the filesystem type. Attempting to run any of the incorrect options from the list will fail with syntax or 'special device not found' errors, confirming their invalidity.

Why Other Options Are Wrong:

• mount -t iso9660 /dev/cdrom / mnt/cdrom: Contains a stray space; '/ mnt/cdrom' is not a valid path.
• mount /dev/cdrom: Missing the mount point argument.
• mount /mnt/cdrom: Missing the device argument.
• All of the above: Cannot be correct because each shown form is flawed.

Common Pitfalls:
Forgetting to create the mount point, omitting either the device or the mount point, or confusing auto-mounting mechanisms (udev/systemd) with manual 'mount' usage.

Final Answer:
None of the above