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.