The accounting records for Social Event Planning Services include the following select unadjusted balances on December​ 31, 2018: Salaries​ Expense, $6,000; Service​ Revenue: $18,000; Unearned​ Revenue, $400; Supplies​ Expense, $600; Rent​ Expense, $300; Depreciation Expensedash​Equipment, ​$200.During December, the company worked with a new client and provided event planning services for an upcoming event. It will receive the full amount of $1,500 when the event is completed in January 2019. As of the end of December 2018, it performed one-third of the services covered by the contract. The company made the accrual adjustments. The balance of Service Revenue, as shown on the adjusted trial balance, should be a ________.
A. debit balance of $1,500
B. credit balance of $19,500
C. credit balance of $19,000
D. debit balance of $20,500