Economies of scale occur when there are

Part 2
A.
increases in​ long-run average costs when output increases.
B.
decreases in​ long-run average costs resulting from increases in output.
C.
decreases in output resulting from decreases in input.
D.
no changes in​ long-run average costs when output increases.

B. decreases in​ long-run average costs resulting from increases in output.