Final answer:
The correct answer is c. Ver. The Ver command is used in Windows operating systems to display the version of the operating system being run. It is an external command not built-in to the command interpreter.
Step-by-step explanation:
The correct answer is c. Ver.
The Ver command is used in Windows operating systems to display the version of the operating system being run. It is an external command because it is not built-in to the command interpreter and is stored as a separate executable file.
For example, if you open the Command Prompt and enter the command ver, it will display information about the version of the Windows operating system you are using.