Operating systems can be grouped based on how a user interacts with them. One type requires the user to type specific text instructions to carry out tasks, offering no visual icons or windows, and it demands that the user memorise exact commands and their correct syntax. The other type presents a screen with visual elements such as icons, windows, menus, and buttons that a user can select with a mouse or touch, making it far more intuitive for someone unfamiliar with typed commands. Together, these two interaction styles make up the two broad types of operating system referred to in this classification.
The other pairings listed describe different concepts entirely. Translators and assemblers are programs that convert code written by a programmer into a form the computer can execute; they are tools used in software development, not categories of operating system. System software and application software describes a broader division of all software into two families, one of which (system software) actually includes operating systems as a subgroup, rather than being two types of operating system itself. Two named operating systems that happen to be related to each other are simply specific examples of real operating systems, not a general classification describing all operating systems by type.
When a question asks for "types" of something, check whether the answer choices describe a genuine category system (like interaction style) rather than a list of unrelated software tools or a pair of specific product names.
