The correct answer is: C. Unix
The Mac OS is a Unix-based operating system developed and marketed by Apple Inc. since 1984. It is the primary operating system for Apple’s Mac computers. Within the market of desktop, laptop and home computers, and by web usage, it is the second most widely used desktop OS, after Microsoft Windows.
The first version of the Mac OS was based on the Unix operating system, which was developed at AT&T’s Bell Labs research center in the late 1960s and early 1970s. Unix was designed to be a multi-user, multitasking operating system, which means that it can be used by multiple people at the same time and can run multiple programs at the same time.
The Mac OS has evolved over time, but it has always retained its Unix roots. This means that the Mac OS is a powerful and versatile operating system that can be used for a variety of tasks. It is also a reliable and secure operating system.
The other options are incorrect because:
- Windows is a proprietary operating system developed by Microsoft.
- Linux is a free and open-source operating system that is based on Unix.
- CMOS is a type of semiconductor memory that is used to store system configuration information.
- None of these is an operating system.