Hello, Need help with this problems within 1 hour, thanks

On April 1, 2012, Geo Insurance Company sold a one-year insurance policy covering the year ended March 31, 2013. Geo collected the full $300 on April 1, 2012. Geo made the following journal entry to record the receipt of cash in advance:

Apr. 1 Dr. Cash 300

Cr. Unearned Revenue 300

Nine months have passed, and Geo has made no adjusting entries. Based on these facts, write the adjusting entry needed by Geo at Dec. 31, 2012.

-------------------------------------------------------------------------------