The correct answer is: D. All of the above
A quotation system obtains potential delivery time data from the production schedule file, the inventory file, and the product catalog file.
The production schedule file contains information about the products that are currently being produced and the expected completion dates for those products. This information can be used to estimate the potential delivery time for a new order.
The inventory file contains information about the products that are currently in stock and the quantity of each product that is available. This information can be used to determine whether the product that is being ordered is currently in stock and, if not, when it is expected to be back in stock.
The product catalog file contains information about all of the products that are available for purchase. This information can be used to determine the product that is being ordered and to provide the customer with information about the product, such as its specifications, price, and availability.
Therefore, a quotation system obtains potential delivery time data from all of the above files.