Which one among the following consists of a list of commands that is executed automatically as the computer system starts up ?

The correct answer is B, AUTOEXEC.BAT. It is the batch file that MS-DOS runs automatically, line by line, every time the computer starts. A batch file is a plain text file of DOS commands with the .BAT extension. During start-up, DOS first reads CONFIG.SYS to load device drivers and set system limits, then loads the command interpreter COMMAND.COM, and finally runs the commands listed in AUTOEXEC.BAT, such as setting the PATH, loading a mouse driver or opening a menu program. Its name simply means 'automatically executed batch file'. Option A is wrong because COMMAND.COM is the command interpreter itself, the program that reads and carries out commands, not a list of commands. Option C is wrong because CONFIG.SYS holds configuration settings and driver lines, not ordinary commands. Option D is wrong because AUTOSTART.BAT is not a standard DOS start-up file. Exam tip: CONFIG.SYS configures, COMMAND.COM interprets, AUTOEXEC.BAT runs commands at boot.