Fitzgerald Company sold 800 tracking units to Whitefish Company for $600 each. Whitefish has 60 days to return the unused goods. Fitzgerald believes that a good estimate of total items that will be returned by Whitefish is 80 units. Prior to Fitzgerald's year end, Whitefish has returned 50 units. Whitefish still has 25 days to make returns. What amount should Fitzgerald report in the Refund Liability account related to this activity on its year-end balance sheet? a. $18,000 b. $48,000 c. $30,000 d. $15,000