The stock/requirements list displays:___. A. Changes in the planning situation since MRP was run.
B. MRP elements at an aggregation level.
C. All MRP elements for a material.
D. Required materials per production version.
E. All materials needed per MRP element.

E. All materials needed per MRP element.

Explanation:

Stock Requirement List is known to be a dynamic list that shows the current status of requirement and sources for that materials. It has been arranged in such a way that any changes in the procurements or needs would be displayed in the list.  it is dynamic as it is updated each time it is displayed.

The stock/requirements list displays All materials needed per MRP element

u = 30

continuing your method

= +

subtract from both sides

= - thus

= -

= ⇒ u = 30