Why did Microsoft choose “C” for the default drive in Windows? Is there a story behind this?

 The choice of the letter "C" for the default drive in Windows goes back to the MS-DOS operating system. When MS-DOS was developed, it needed a way to differentiate between various disk drives.

The letters "A" and "B" were already assigned to floppy disk drives, so the next logical letter was "C" for the hard disk drive. This convention continued into subsequent versions of Windows, establishing "C" as the default letter for the primary hard drive.