Can you please help me answer the following question?

Sydney & Caesar Law Firm uses the accrual basis to keep their accounting records. During 2018, they collected $540,000 from clients. On December 31, 2017 they had accounts receivable of $61,000. On December 31, 2018 they had accounts receivable of $81,000 and unearned revenue of $15,000. Using the accrual basis, how much is Sydney & Caesar Law Firm's service revenue for 2018? O A. $479,000 O B. $560,000 C. $535,000 D. $545,000