4. Selected accounts for Alex Company are presented below before making closing entries on March 31. Salaries Expense, CNY8,800 Service Revenue, CNY18,000 Supplies Expense, CNY1,100 Retained Earnings, CNY12,000 Rent Expense, CNY3,000 Dividends, CNY2,500 Advertising Expense, CNY1,000 Depreciation Expense, CNY1,500 Requirement: Prepare the closing entries on March 31, and calculate operating income for the month of March.(2)