Which one of the following statements best defines the purpose of a Product Breakdown Structure (PBS)?

Which one of the following statements best defines the purpose of a Product Breakdown Structure
(PBS)?
a. To define the hierarchy of deliverables that are required to be produced on the project.
b. To define how the products are produced by identifying derivations and dependencies.
c. To establish the extent of work required prior to project commissioning and the handover.
d. To identify the health and safety strategies and procedures to be used on the project