State whether each of the following events will result in a movement along the market supply curve of agricultural labor in the United States or whether it will cause the market supply curve of agricultural labor to shift. If the supply curve shifts, indicate whether it will shift to the left or to the right and draw a graph to illustrate the shift.
a. The agricultural wage rate declines.
b. Wages outside agriculture increase.
c. The law is changed to allow for unlimited immigration into the United States.