Juana has the following data for two years Revenue 2020 2021 '000s '000s 450 550 Cost of sales 150 250 Inventory 78 88 Accounts receivable 98 Accounts payable 100 Gross profit Operating expenses Which of the following is true? 96 98 102 ? ? 150 150 Gross profit margin has increased in 2021 as compared to 2020 O Gross profit margin has decreased in 2021 as compared to 2020 O Gross profit margin has remained unchanged in 2021 as compared to 2020