I just wanted to install a command-line system from my Ubuntu 12.04.3 LTS ISO and the option for that is missing. Am I missing something in the process or what could be the fault? Trying to use it within a VirtualBox VM.

I just wanted to install a command-line system from my Ubuntu 12.04.3 LTS ISO and the option for that is missing. Am I missing something in the process or what could be the fault? Trying to use it within a VirtualBox VM.

You will need to install Ubuntu Server instead of Ubuntu desktop.
Ubuntu server comes without the GUI part of Ubuntu (which means it doesn't have the ubuntu-desktop meta-package installed). So it only has a command line.
During installation of Ubuntu Server, it asks you what packages/servers you want to install (apache, mysql, etc.). Of course you will be able install them later, even if you didn't choose the packages during installation.
There is no such option in the standard installation medium.
You could alternatively install Ubuntu Server or use the minimal installation medium.