Table 2.2 -Krystal Runs a Nail Salon and Needs to Decide How

Multiple Choice

Table 2.2

-Krystal runs a nail salon and needs to decide how many hours to stay open. Table 2.2 illustrates her marginal costs of staying open for each additional hour. Suppose that Krystal's marginal benefit of staying open per hour is $18. If she is following the marginal principle, how many hours should Krystal stay open?

A) 3 hours
B) 4 hours
C) 6 hours
D) 7 hours