Use the Following Data to Answer the Question

Use the following data to answer the question. The letters A, B, and C designate three successively larger plant sizes. Economies of scale in plant ATC-A are realized over the to levels of output; diseconomies of scale exist over the to levels of output.

A) 10, 30; 40, 100
B) 10, 40; 80, 100
C) 10, 50; 60, 100
D) 10, 70; 80, 100