Answer:
b. average total costs decline as output increases.
Explanation:
Economies of scale refer to the cost advantage when it become reaped by the companies in the case when there is an efficient production
As the cost would be allocated to the larger number of goods. Here cost would be fixed as well as variables one. ALso, in this the size of the organization would matter a lot
So when the output would rise the average total cost would fall
Therefore the option b is correct