The UNIX sytem uses a/an ________ stored at the beginning of a some files to indicate roughly the type of file.

The UNIX sytem uses a/an ________ stored at the beginning of a some fi

1.	The UNIX sytem uses a/an ________ stored at the beginning of a some files to indicate roughly the type of file.
A.	identifier
B.	extension
C.	virtual number
D.	magic number
Answer» E.