First Fleet Company Is a Two-Division Firm and Has the Following

First Fleet Company is a two-division firm and has the following information available for this year:
$$\begin{array} { l r } \text { Common fixed costs } & \$ 400,000 \\\text { Direct fixed costs of Division A } & 100,000 \\\text { Direct fixed costs of Division B } & 200,000 \\\text { Sales revenue of Division A } & 600,000 \\\text { Sales revenue of Division B } & 900,000 \\\text { Variable costs of Division A } & 120,000 \\\text { Variable costs of Division B } & 180,000\end{array}$$ What is Division A's contribution margin?

A) $ 420,000
B) $ 450,000
C) $ 480,000
D) $(120,000)