What is a Stock Keeping Unit (SKU)?

A.
A number that identifies the entire preconfigured package as purchased by a customer

B.
A number that identifies a unit that includes only standard configurations that are unchangeable
and remain the same across regions

C.
A number that identifies a unit with all the options added but does not include service warranty
01 software

D.
The factory basic build with all fixed components (modules) installed

Explanation:

Reference:
http://en.wikipedia.org/wiki/Stock-keeping_unit