Final answer:
The situation that represents vertical integration is when Andrew Carnegie owns all of the companies that produce goods needed to make steel.
Step-by-step explanation:
Vertical integration is a method of growth where a company acquires other companies that include all aspects of a product's lifecycle, from the creation of raw materials through the production process to the delivery of the final product. In the given options, the situation that represents vertical integration is when Andrew Carnegie owns all of the companies that produce goods needed to make steel. Carnegie effectively controlled the entire process of steel production, from the mines to the railroads, allowing him to cut costs and ensure a quality product.