Answer:
Economies Of Scale
Step-by-step explanation:
Average total cost(ATC) refers to total cost incurred per unit of output produced.
ATC at level of 90 canisters = $1050/90 canisters = $ 11.67 per canister
ATC at level of 120 canisters= $1200/120 canisters = $10 per canister
As can be seen, the average total cost has reduced.
Economies of scale is defined as the phenomena when in the long run, average total cost reduces along with an increase in the output.
The reasons attributable to this phenomena being, increase in labor efficiency and better utilization of resources coupled with bulk quantity of inputs purchased at a lower cost, which lowers the cost of production in the long run.