A firm purchased a two-year insurance policy for $8,160 on July 1, 20X1. The $8,160 was debited to the Prepaid Insurance account. On December 1, 20X1, a firm signed a contract with a local radio station for advertising that will extend over a one-year period. The firm paid $16,080 in advance and debited the amount to Prepaid Advertising. Prepare end-of-month adjusting entries for each of the above situations.