MacMan, Inc. reported the following data: 2019 2018 Amount Percentage Revenues $6,360 $4,990 $1,370 27.45% Cost of goods sold 3,380 2,400 980 40.83% Gross profit 2,980 2,590 390 15.06% Operating expenses: Sales and marketing expense 710 620 90 14.52% General and administrative expenses 480 435 45 10.34% Research and development expense 500 460 40 8.7% Other expense 410 695 (285) (41.01)% OA. increased by 27.45% OB. decreased by 27.45% OC. decreased by 40.83% OD. increased by 40.83%