Final answer:
Exceeding WMP-5 sortie rates or flying hours can shorten aircraft sustainable duration below strategic planning guidance.
Step-by-step explanation:
The statement a) True is correct. When the WMP-5 sortie rates or flying hours exceed the allowable limits, it can shorten the sustainable duration of an aircraft below what is prescribed in strategic planning guidance. This is because excessive sorties or flying hours can put additional stress on the aircraft systems and components, potentially leading to increased maintenance and repair needs and reducing its overall lifespan.