Answer:
C) debit Cash $540 and Service Revenue, $280, credit Accounts Receivable, $820
Explanation:
The correct journal entry should have been:
Dr Cash 820
Cr Accounts receivable 820
But since the transaction was erroneously recorded as:
Dr Cash 280
Cr Sales revenue 280
an adjusting entry is necessary for the difference:
Dr Cash 540
Dr Sales revenue 280
Cr Accounts receivable 820
This way cash account will have increased by $280 + $540 = $820, sales revenue will remain unchanged $280 - $280 = $0, and accounts receivable will decrease by $820.