Table 1-1 Lydia Runs a Small Nail Salon in the in the Town

Multiple Choice

Table 1-1
Lydia runs a small nail salon in the town of New Hope. She is debating whether she should extend her hours of operation. Lydia figures that her sales revenue will depend on the number of hours the nail salon is open as shown in the table above. She would have to hire a worker for those hours at a wage rate of $10 per hour.
-Refer to Table 1-1. What is Lydia's marginal cost if she decides to stay open for two hours instead of one hour?

A) $10
B) $20
C) $25
D) $40