Rather than use a WBS$,$ your team developed a bill of materials to define the project$$s work components. A customer review of this document uncovered that a scope change was needed, because a deliverable had not been defined, and it led to the need to write a change request. This is an example of a change request that is required because it is the result of$$

a

An error or omission in defining the scope of the project

b

A change to the scope baseline

c

A value$-$adding change

d

An external event