Many Economists Believe That in Our Modern Economy, Firm Size

Many economists believe that in our modern economy, firm size is most directly determined by

A) concentration ratios that decrease as the number of firms decreases
B) diseconomies of scale that make it less costly to increase firm size
C) easy entry of new firms when there are economies of scale
D) government policies that dictate optimal firm investment levels
E) modern technology that gives an advantage to large-scale production methods