Gamma Corporation has a December 31st year-end. At the beginning of the year, the balance of the unearned service revenue account was $1,500. At year-end, $400 had not been earned, but the balance of the unearned service revenue account was still $1,500. Which account should Gamma credit on December 31st to properly adjust this account? [Select] What account would Gamma debit in its December 31st adjusting journal entry? [Select] What would be the effect on net income if Gamma fails to record the adjusting journal entry on December 31st? [Select] What is the amount of the debit and credit in the December 31st adjusting journal entry? [Select]