On May 1, Marcelli Marketing Company received $1,500 from Franco Marcelli for a marketing campaign effective from May 1 of the current year to April 30 of the following year. The cash receipt was recorded as unearned revenue and at year-end on December 31, $1,000 of the fees had been earned. Assuming adjustments are only made at year-end, the adjusting entry on December 31 would be: