A consumer-packaged goods company is producing large volumes of hair shampoo and conditioners serving multiple markets. Which fulfillment strategy is it using in this case?

Assemble-to-order involves producing components and then assembling them into final products only after receiving customer orders. This strategy is typically used for products that can be customized or configured differently based on specific customer requirements, which does not align with the large volume production described in the question.

In a make-to-order strategy, products are only manufactured once an order is received. This approach is commonly utilized for customized or specialized products, which contrasts with the scenario of producing large volumes of standard hair care products intended for multiple markets.

Vertical integration refers to a company's strategy to control multiple stages of production or supply chain processes, either by owning suppliers or distributors. While this may apply to the company's operations in a broader sense, it does not specifically address the fulfillment strategy used for producing large volumes of hair shampoo and conditioners.