-Refer to Figure 4

-Refer to Figure 4.1, the increase in output from point A to B and from point B to C happens because

A) more workers will produce more.
B) better workers are usually hired after the earlier ones.
C) a small number of workers cannot take as good advantage of the division of labor as a larger number.
D) eventually workers are up against the fact that there are fixed inputs and more workers do not add as much.