The correct answer is B.
OBJ-3.4.3: PRINCE2’s recommend approach to defining and analyzing the products is to (1) write a project product description, (2) create a product breakdown structure, (3) write product descriptions, and (4) create a product flow diagram. A product flow diagram may be helpful in identifying and defining the sequence in which the products of the plan will be developed and any dependencies between them. The product flow diagram also helps to identify dependencies on any products outside the scope of the plan. It leads naturally to the consideration of the activities required and provides the information for other planning techniques, such as estimating and scheduling.