On November 21st, Jerry's accounting firm collected $20,000 from John for work to be performed in the future. On December 10th, the accounting firm completed 60% of John's work. What is the journal entry made on December 10th?

A) Debit service revenue $12,000 and credit unearned revenue $12,000

B)Debit unearned revenue $20,000 and credit cash $20,000

C) Debit cash $20,000 and credit unearned revenue $20,000

D) Debit unearned revenue $12,000 and credit service revenue $12,000