Explanation:

MS-Word (Microsoft Word) is a quintessential example of application software. Application software is designed to perform specific tasks or functions for the end-user, such as word processing, spreadsheet calculations, web browsing, or graphic design. It runs on top of an operating system and utilizes the computer's resources to achieve its purpose. Option (a) "Operating system" (e.g., Windows, macOS) is system software that manages hardware and software resources. Option (c) "Processing device" refers to hardware components like the Central Processing Unit (CPU). Option (d) "Input device" refers to hardware peripherals like a keyboard or mouse. MS-Word is clearly a program for a specific user task.