Refer to the following mentioned data. Net sales Cost of products sold Gross margin (In millions) 2017 2016 2015 $ 34,080 $30,001 $ 26, 253 14,272 13,238 13,804 $ 19,808 $ 16,763 $ 12,449 Required: a. Calculate the gross profit ratio for each of the past three years. (Round your answers to 2 decimal places.) 2017 2016 2015 b. Assume that Campbell's net sales for the first four months of 2018 totaled $12.80 billion. Calculate an estimated cost of goods sold and gross profit for the four months, using the gross profit ratio for 2017. (Round intermediate calculations to 2 decimal places. Enter your answers in millions rounded to nearest whole number i.e., 5,000,000 should be entered as 5).) million Cost of goods sold Gross profit million