Answer:
Windows
Explanation:
The most commonly used OS today is Microsoft Windows. Microsoft's founder and President Bill Gates created the operating system way back then.
Windows is the default standard in most computers you see today and is in use in across millions/billions of devices.
Mac and Linux are similar; Mac OS, or SierraOS, is a custum Linux base OS. Both of these operating systems are popular now, but still not as widespread popular as Windows.
SierraOS only targets Mac/Apple Users. Linux targets coders.
