Final answer:
Engineer-to-Order (ETO) is the manufacturing strategy where the product is designed, engineered, and built to specifications only after the order has been received. The correct option is: a).
Step-by-step explanation:
The manufacturing strategy in which the product is designed, engineered, and built to specifications only after the order has been received is called Engineer-to-Order (ETO).
Engineer-to-Order (ETO) manufacturing is used when products are unique and extensively customized for the specific needs of individual customers. It involves designing and engineering the product in response to a customer's order, rather than having pre-designed products in stock.
Make-to-Stock (MTS), Make-to-Order (MTO), and Assemble-to-Order (ATO) are other manufacturing strategies, but they are not the correct answer for this question.