Which of the following statements about productivity is false?
a) the law of diminishing returns states that, all else equal, returns to one type of input eventually decrease as more of that input is used.
b) At low levels of production, when a firm first adds extra worker it increases marginal productivity because of specialization.
c) Diseconomies of scale arise due to managerial complexity
d) Economies of scale cause the long-run supply curve to have a negative slope.