Which functionality would you include in the product category of the marketing mix?
A. substitute goods for current product
B. product discounts
C. after-sales service
D. product image used in advertisement

The after sales services are included in the product category of market mix.  Option C

Explanation:

The set of ideas or actions taken by a business entity or a company to promote its product or brand in the market. The four P’s of marketing mix are namely,

From the given, discounts comes under pricing, product image used in advertising comes under promotion and substitute goods belong to a different topic. After-sales services comes under the service branch of the product category.

whats the

the first successful, urban blues recording, selling more than 75,000 copies, was made in year 1920.

mamie smith recorded the first commercially successful example of the urban blues,   with the recording of “crazy blues”."crazy blues" was recorded on august 10, 1920, in new york city. within a month of the release of “crazy blues” it had sold 75,000 copies.