Accounting homework help

Betty Carson has performed $500 of CPA services for a client but has not billed the client as of the end of the accounting period. What adjusting entry must Betty make?

(a) Debit Cash and credit Unearned Revenue.

(b) Debit Accounts Receivable and credit Unearned Revenue.

(c) Debit Accounts Receivable and credit Service Revenue.

(d) Debit Unearned Revenue and credit Service Revenue.

I know that this is asking of much but all I need is just this one answer and I'll be done with my quiz, so if anyone wouldn't mind helping please do just for this one question.

It should be 'C.' No cash was received and the work is completed. Accounts Receivable are an asset account and a debit will increase it's value. Revenue accounts increase owners equity so it has a credit balance.