The relationship between advertising and product differentiation is a. irrelevant; firms with differentiated products do not need to advertise. b. zero; there is no relationship between product differentiation and advertising. c. negative; the more differentiated the product, the less a firm is likely to spend on advertising. d. positive; the more differentiated the product, the more a firm is likely to spend on advertising.

d.positive; the more differentiated the product, the more a firm is likely to spend on advertising.

Explanation:

A product can be defined as any physical object or material that typically satisfy and meets the demands, needs or wants of customers. Some examples of a product are mobile phones, television, microphone, microwave oven, bread, pencil, freezer, beverages, soft drinks etc.

Advertisement refers to the promotional multimedia messages designed and developed to make the products or services of a company known to its customers and potential customers.

Product differentiation refers to the differences imposed on consumers by the seller of a product. Thus, it typically makes a product better for some consumers and worse for others.

Hence, the relationship between advertising and product differentiation is positive; the more differentiated the product, the more a firm is likely to spend on advertising so as to convince and spur consumers into buying the product.