-Refer to the Exhibit

$\begin{array}{lrrrr}\text { Taxable income } & \$ 1,000 & \$ 3,000 & \$ 9,000 & \$ 27,000 \\ \text { Tax payments } & \$ 100 & \$ 200 & \$ 400 & \$ 800\end{array}$
-Refer to the exhibit.What is the taxation system?  

A)  progressive through all levels of income 
B)  proportional throughout all levels of income 
C)  regressive throughout all levels of income 
D)  flat