Final answer:
A command line interface is where users input all commands by typing, which was typical in systems like the 1980s Bulletin Board Systems. so, option a is the correct answer.
Step-by-step explanation:
A command line interface is one where the user types in all the commands. This contrasts with a graphical user interface where interactions are mainly through graphical elements like windows, icons, and menus. Early computing systems, like Bulletin Board Systems (BBS) in the 1980s, used command line interfaces that relied on text and simple graphics. These BBS were quite limited compared to today's websites, but at the time, they were innovative and paved the way for modern communication technologies.
A command line interface is a text-based interface where the user types in all the commands.
A command line interface is one where the user types in all the commands. It is a text-based interface that allows users to interact with a computer by entering commands as text. Command line interfaces are commonly used in operating systems such as Linux and Unix.