A standardized product is a product

A. That is unique to one producer

B. Where the demand function is downward sloping for both the firm and the industry

C. Which is produced according to government regulations

D. That has many perfect substitutes

The correct answer here is D) which has many perfect substitutes.

Explanation:

A product is a standardize product regardless of which firm has furnished the product, the consumers will regard these furnished products as identical no matter which firm has made it, because they are only concerned with the size and quality of the product, so we can say that standardize products are perfect substitutes and there are many commodities in the market which are standardize products like grains, milk, curd etc.