-How Much Is the Average Propensity to Save When Disposable

$$\begin{array} { c c } \text { Disposable Income } & \text { Consumption } \\0 & \$ 200 \text { billion } \\\$ 200 \text { billion } & 300 \text { billion } \\400 \text { billion } & 400 \text { billion } \\600 \text { billion } & 500 \text { billion } \\800 \text { billion } & 600 \text { billion }\end{array}$$
-How much is the average propensity to save when disposable income is $400 billion?

A) 0
B) .25
C) .50
D) .75
E) 1.0