Table 1-3 Santiago Runs a Comic Book Store in the in the Town

Multiple Choice

Table 1-3
Santiago runs a comic book store in the town of East Arbor. He is debating whether he should extend his hours of operation. Santiago figures that his sales revenue will depend on the number of hours the store is open as shown in the table above. He would have to hire a worker for those hours at a wage rate of $18 per hour.
-Refer to Table 1-3. What is Santiago's marginal cost if he decides to stay open for two hours instead of one hour?

A) $18
B) $36
C) $38
D) $102