Which Is True of an Autonumber Key

Multiple Choice

Which is true of an autonumber key?

A) It can be used,with consecutive integer values,when no other primary key is available.
B) If a "natural" primary key,such as product code,is available,it is a better option than an autonumber primary key; it will lead to more accurate query results.
C) It is best used as a primary key in conjunction with another primary key,such as a Social Security number.
D) It has often been used in Access database tables,but it shouldn't be used in an Excel Data Model.