The Accounting Records for Patricia Event Planning Services Include the Following

The accounting records for Patricia Event Planning Services include the following select unadjusted balances on December 31,2016: Salaries Expense,$6,000;Service Revenue: $19,000;Unearned Revenue,$400;Supplies Expense,$600;Rent Expense,$300;Depreciation Expense-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 $2,100 when the event is completed in January 2017.As of the end of December 2016,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 $21,100
B) credit balance of $19,000
C) debit balance of $2,100
D) credit balance of $19,700