4. In Caymus Company’s December 31 trial balance, a credit balance of

$31,500 appears in Unearned Fee Income. This amount represents cash received from a customer on November 1 covering work to be performed by Caymus in November through January. At December 31, Caymus had earned $10,500 of the amount received on November 1.
What account will be debited and what account will be credited in the adjusting entry on December 31? What is the amount of the adjustment?