The following information is provided for Nguyen Company and Northwest Corporation. (in $ millions) Nguyen Company Northwest Corporation Net Income 2020 $375 $490 Net sales 2020 1,500 4,100 Total assets 12/31/18 1,200 2,500 1,250 3,100 Total assets 12/31/19 Total assets 12/31/20 1,350 4,200 What is Northwest's return on assets for 2020? a. 12.7% b. 13.4% c. 17.5% d. 28.8%