Choice "C" is correct. Preventative maintenance costs are conforming costs, which are inversely related to nonconforming costs such as rework costs.
Choice "a" is incorrect. Both employee training costs and inspection expenses are conforming costs. They are not inversely related.
Choice "b" is incorrect. Both warranty costs and liability claims are nonconforming costs. They are not inversely related.
Choice "d" is incorrect. Both Inspection expenses and redesign of product expenses are conforming costs. They are not inversely related.
