General Nuisance, Inc. shipped 100 million coupons in products it sold in 2016. The coupons are redeemable for thirty cents each. General anticipates that 70% of the coupons will be redeemed. The coupons expire on December 31, 2017. There were 45 million coupons redeemed in 2016, and 30 million redeemed in 2017.

4a. What was General's coupon liability as of December 31, 2016?

4b. What was General's coupon promotion expense in 2016?

4c. What was General's coupon promotional expense in 2017?.