Prepare the adjusting journal entries required on December 31, 2020, for Walker Corp. using the following information. Assume that no adjusting journal entries were recorded in 2020 prior to year-end. a. Interest expense of $300 for the month of December 2020 will be paid in January 2021. b. Unbilled revenue for services performed in December 2020 is $1,000. The company will prepare and forward invoices for this amount in January 2021 to customers with a 30-day collection term. c. $3,000 cash was received in advance on November 30, 2020, for future services to be performed by Walker Corp. and was recorded as deferred service revenue. The services were performed on December 20, 2020. d. Walker Corp. acquired a two-year insurance policy on January 1, 2020, for $9,600 cash that was recorded initially as prepaid insurance. e. Depreciation on equipment is $12,000 for 2020.