Speedy Cleaning Service began its operations on December 1, 2019. The following transactions took place during its first month of operations. The company uses the calendar year as its reporting period. During December, the company completed the following transactions. Summary of Transactions: Dec. 1 Stockholders invested $14,000 cash in the business in exchange for common stock. Dec. 2 Purchased a used truck for $10,000, paying $3,000 cash and the balance on account Dec. 3 Dec. 5 Dec. 12 Purchased cleaning supplies for $800 on account. Paid $1,800 on a 1-year insurance policy, effective December 1. Billed customers $3,800 for cleaning services. Paid $1,000 of the amount owed on truck, and $400 of the amount owed on cleaning supplies. Dec. 18 Dec. 20 Paid $1,600 for employee salaries. Dec. 21 Collected $1,400 from customers billed on December 12. Billed customers $1,500 for cleaning services. Dec. 25 Dec. 31 Paid gasoline for the month on the truck, $400. Dec. 31 Declared and paid a $600 cash dividend. Additional Data Determined at December 31, 2019: a. Unbilled fees for services performed at December 31 were $1,300. b. Depreciation on the truck was $200 for the month. c. One-twelfth of the insurance expired by December 31. d. An inventory count shows $100 of cleaning supplies on hand at December 31. e. Accrued but unpaid employee salaries were $500. 8. Prepare the closing entry for the month ended December 31, 2019, and then post it to the T-accounts. 9. Prepare a post-closing trial balance at December 31, 2019