Final answer:
The optimum production quantity is the output level where the cost per unit is the lowest due to economies of scale. It is 150 units for toaster ovens and 40,000 units for semiconductors, as per the given data.
Step-by-step explanation:
The question pertains to finding the optimum production quantity for a firm, which is the level of output where the firm achieves the lowest cost per unit. According to the information provided, economies of scale are experienced in many industries where as the quantity of output increases, the cost per unit goes down, up to a certain point. From the data given, it is evident that this optimal scale of production, where economies of scale are fully realized, is at the output of 150 units for toaster ovens and 40,000 units for semiconductors. Beyond these points, the average cost of production does not decline further. Therefore, these quantities represent the optimum production quantity for these products, where the production cost is at its lowest.