7. With the table below, answer the questions which follow.

Labor Total Output

0 0

1 1,500

2 3,400

3 5,100

4 6,500

5 7,400

6 8,000

7 8,300

8 8,300

9 8,200

a. Diminishing returns begins with which unit of labor?

b. What is the marginal product of the fourth unit of labor?

c. What is the average product of the sixth unit of labor?

d. Marginal product becomes negative with which unit of labor?