​Table 14-17 the Table Below Shows the Price and Cost Information for Information

Multiple Choice

​Table 14-17
The table below shows the price and cost information for a firm that operates in a perfectly competitive market.
-​Refer to Table 14-17. The marginal cost of the fourth unit is

A) ​$28.
B) ​$32.
C) ​$5.
D) ​$7.