Answer:
To record the sales of gift cards
Dr Cash 3,500
Cr Unearned revenue 3,500
To record the redemption of sales cards
Dr Unearned revenue 728
Cr Sales revenue 700
Cr Sales taxes payable 28
The balance of the unearned revenue account:
Debit Credit
$3,500
$728
$2,772
The unearned revenue account has a $2,772 credit balance on December 31.
Both unearned revenue and sales taxes payable are liability accounts that have a credit balance.