6. Knupp Electric began operations in 2020 and provides a one year warranty on the curling irons it sells. They estimate that 4,000 of the 120,000 curling irons sold in 2020 will be returned for repairs and that these repairs will cost $4 per unit. The cost of repairing 3,000 curling irons sold in 2020 presented for service in 2020 was $15,000. Carter should report: A) warranty expense of $16,000 for 2020. B) warranty expense of $4,000 for 2020. C) estimated warranty liability of $16,000 on December 31, 2020. D) no warranty obligation on December 31, 2012, since this is only a contingent liability