Which is not an external command? A. Edit B. XCOPY C. Sys D. None of the above

The correct answer is: A. Edit

An external command is a command that is not built into the operating system. It is a program that is stored on a disk and must be loaded into memory before it can be executed.

Edit is an internal command. It is a command that is built into the operating system and does not need to be loaded into memory before it can be executed.

XCOPY is an external command. It is a command that is used to copy files from one location to another.

Sys is an external command. It is a command that is used to display or modify system information.

Therefore, the correct answer is A.