Fats Feet Company is a two-division firm and has the following information available for this year: Common fixed costs $ 400,000 Direct fixed costs of Division A 100.000 Direct fixed costs of Division B 200,000 Sales revenue of Division A 600.000 Sales revenue of Division B 900.000 Variable costs of Division A 120,000 Variable costs of Division B 180.000 What is Division A's contribution margin? O $(120,000) O $ 480,000 O $ 420,000 O $ 450,000