On October 31 of the current year, a contract was signed and a cheque received for services to be performed by October 31 of the following year. The Unearned Service Revenue account was credited for $4,800. Assuming services were performed evenly during the remainder of the year, the adjusting entry on December 31 will involve a: O credit to Service Revenue $800 O credit to Unearned Service Revenue $800 credit to Service Revenue for $4,000 O debit to Unearned Service Revenue $4,000