During September, Excom sold 100 radios for $50 each and provided a two-year warranty with each unit. Each radio cost Excom $30 to produce. If 5% of the goods sold typically need to be replaced over the warranty period and one is actually replaced during September, for what amount in September would Excom debit Product Warranty Expense?

a. $50

b. $30

c. $120

d. $150