The correct answer is C. COMMAND.COM.
COMMAND.COM is the command-line interpreter for MS-DOS and OS/2. It is responsible for executing commands entered by the user at the command prompt. It also provides a number of built-in commands, such as DIR, CD, and DEL.
MS-DOS.SYS is a system file that contains the basic instructions that DOS needs to start up. It also contains information about the hardware configuration of the computer.
CONFIG.SYS is a configuration file that contains settings that control how DOS operates. These settings can include the amount of memory that is available to DOS, the location of the boot drive, and the type of keyboard that is installed.
SYSTEM.INI is a configuration file that contains settings for Windows. These settings can include the appearance of the desktop, the location of program files, and the type of printer that is installed.
None of the above options are correct.