hi friends,

the choices are:

a. it allows one to easily identify the breakdown level of the item in the resource structure.  

b. it describes the coding structure used by the performing organization to report financial information in its general ledger.

c. It is the collection of unique identifiers generally assigned to wbs items.

d. it defines ethical behavior in the project.

The answer is  [c] but I am not sure why is a and b wrong?