Explanation:

C++ is a powerful, general-purpose programming language that supports multiple programming paradigms, including object-oriented, generic, and procedural programming. It is widely used for system programming, game development, embedded systems, and more. Option (a) 'An operating system' is incorrect; operating systems like Windows or Linux are built using languages like C and C++, but C++ itself is not an OS. Option (c) 'A software' is too general; while C++ is used to *create* software, C++ itself is the language used for development, not an application or piece of software in the typical user sense. Therefore, the most precise classification is 'A programming language'.