E (For entries with a $0 balance, make sure to enter to in the appropriate coll Round the contribution margin percentage to the nearest whole percont.) Variable Fixed Total Operating Contribution Case Revenues Costs Costs Costs Income Margin Percentage a. 2100 $ 200 300 $ 600 $ 1,500 1900 b. $ 2,600 400 800 $ C. $ 700 $ 300 400 $ 700 % d. $ 1,400 $ 400 50 % 1400 $ 1800 $