Final answer:
Economies of scale and efficient operations do not represent methods of product differentiation; they refer to cost and operational efficiencies. Differentiation emphasizes unique features, customer perceptions, and intangible aspects that make products stand out.
Step-by-step explanation:
The option that does not represent a way in which a good or service can be differentiated is c. Economies of scale and efficient operations. Differentiation involves making a product or service stand out from competitors through unique characteristics. These characteristics can include physical aspects of the product, the location from which it is sold, intangible aspects such as customer service, and the perceptions or prestige associated with the product. Economies of scale and efficient operations, while important for business success, pertain to production cost advantages and operational efficiency, rather than distinguishing a product in the minds of consumers in the marketplace.