After the success of the company's first two months, Santana Rey continues to operate Business Solutions. The November 30,2021 , unadjusted trial balance of Business Solutions (reflecting its transactions for October and November of 2021) follows. Business Solutions had the following transactions and events in December 2021. BUSINESS SOLUTIONS Statement of Retained Earnings For Three Months Ended December 31, 2021 \begin{tabular}{|l|l|} \hline Retained earnings, October 1,2021 & \\ \hline & \\ \hline & \\ \hline Retained earnings, December 31,2021 & \\ \hline \end{tabular} a. The December 31 inventory count of computer supplies shows $630 still available. b. Three months have expired since the 12 -month insurance premium was paid in advance. c. As of December 31, Lyn Addie has not been paid for four days of work at $105 per day. d. The computer system, acquired on October 1 , is expected to have a four-year life with no salvage value. e. The office equipment, acquired on October 1 , is expected to have a five-year life with no salvage value. f. Three of the four months' prepaid rent have expired