Explanation:

The correct answer is (c) a security utility. Antivirus software is a specialized type of utility software designed to protect computer systems from malicious software (malware) such as viruses, worms, Trojans, ransomware, and spyware. Its primary function is to detect, prevent, and remove these threats, thereby enhancing the overall security and integrity of the computer system. It falls under the broader category of security software, which provides tools for system protection. (a) Business software is a broad category for applications that help businesses operate, such as accounting software, customer relationship management (CRM) systems, or enterprise resource planning (ERP) software. While businesses use antivirus software, its core function is security, not direct business operations. (b) An operating system (OS) is the fundamental software that manages computer hardware and software resources, providing common services for computer programs (e.g., Windows, macOS, Linux). Antivirus software runs *on* an operating system; it is not an operating system itself. (d) An office suite is a collection of productivity applications typically used in an office environment, such as word processors, spreadsheets, and presentation software (e.g., Microsoft Office, LibreOffice). Antivirus software is not part of an standard office suite. (e) None of these is incorrect, as option (c) accurately describes the nature and purpose of antivirus software.