P19-1A. Net Income Planning Selected operating data for Oakbrook Company in four independent situations are shown below. B D Sales.. Variable expense Fixed expense Net income before tax (loss). Units sold.. Unit contribution margin.. Contribution margin ratio $300,000 $ a $ b. $ 20,000 30,000 5.20 $ c. $91,000 $62,000 $15,000 d. $ 7.00 $ f. $43,200 $28,800 $260,000 $ g $ 89,000 $ (11.000) 0.4 h. Required Fill in the blanks for each independent situation. Show your calculations