The following question is taken from the July to December 2016 exam period. The following spreadsheet shows the calculation of a company's profit. A B 1 $ 2 Sales revenue 20,000 3 Variable production costs 5,000 4 Fixed production costs 3,000 5 Gross profit 12,000 6 Variable selling costs 1,000 7 Fixed selling costs 500 8 Profit 10,500 Which formula would calculate contribution?