Consider total cost and total revenue, given in the following table:
| Quantity (units) | Total cost ($) | Marginal cost ($) | Total revenue ($) | Marginal revenue ($) | Profit |
|---|---|---|---|---|---|
| 0 | 8 | 0 | |||
| 1 | 9 | 8 | |||
| 2 | 10 | 16 | |||
| 3 | 11 | 24 | |||
| 4 | 13 | 32 | |||
| 5 | 19 | 40 | |||
| 6 | 27 | 48 | |||
| 7 | 37 | 56 |
a) In the final column, enter profit for each quantity.
b) In order to maximize profit, how many units should the firm produce?
a. 4.
b. 5.
c. 6.
d. 7.