Which of the following is NOT a key component in building quality into products?

Quality of marketing is not considered a key component in building quality into products because it primarily focuses on how a product is promoted and sold rather than how the product itself is designed, manufactured, and delivered.

In contrast, quality of design involves creating product specifications that meet customer expectations and needs, ensuring that the product is conceived with the necessary features and functionality. Quality of conformance refers to the ability of the product to meet the established design specifications consistently during production. Quality of service pertains to how well the product is supported post-sale, including customer service and warranty policies.

Each of these elements directly contributes to the overall quality and satisfaction associated with the product, while marketing, although important for visibility and sales, does not affect the inherent quality of the product itself.