The correct answer is: B. bill of materials file
A bill of materials (BOM) is a list of the components that make up a product, along with the quantity of each component required. It is used to plan and control production, and to ensure that the correct components are ordered and available when needed.
An item master file is a database that contains information about all of the items that a company uses, including their description, price, and supplier. It is used to track inventory levels and to generate purchase orders.
An operations file is a database that contains information about the steps involved in manufacturing a product, including the time and cost required for each step. It is used to plan and schedule production, and to track progress against the schedule.
Therefore, the only option that is a type of product structure file is B. bill of materials file.