To recover the root password, the user needs to boot the system using a boot disk floppy. Then, they need to mount the root partition and edit the /etc/passwd file to remove the root password. Option C is the correct answer.

Option A is incorrect because it does not provide any solution to recover the root password.

Option B is incorrect because it suggests to mount the main partition instead of the root partition. Editing the /etc/passwd file of the main partition will not affect the root password.

Option D is incorrect because it suggests to edit the /tmp/passwd file instead of the /etc/passwd file. The /tmp directory is used for temporary files, and editing the /tmp/passwd file will not affect the root password.

Option E is incorrect because it suggests to edit the /etc/passwds file instead of the /etc/passwd file. There is no such file as /etc/passwds, so this option is invalid.

The Answer is: C. Mount the root partition, edit the /etc/passwd file to remove the root password, reboot.