In its 2016 annual report, caterpillar inc. reported the following (in millions): 2016 2015 sales $38,537 $47,011 cost of goods sold 28,309 33,546 as a percentage of sales, did caterpillar's gross profit increase or decrease during 2016? select one: a. gross profit increased from 26.8% to 28.6% b. gross profit decreased from 28.6% to 26.5% c. gross profit increased from 71.4% to 73.2% d. gross profit decreased from 73.2% to 71.4% e. there is not enough information to answer the question.