Answer the Question on the Basis of the Following Before-Tax

Answer the question on the basis of the following before-tax consumption schedule for a closed economy: $\begin{array}{l}\text { Gross Domestic }\\\underline{\text { Product (GDP) } } & \underline{\text { Consumption (C) }} \\\$0 & \$ 40 \\100 & 120 \\200 & 200 \\300 & 280 \\400 & 360\end{array}$ Refer to the data.If a lump-sum tax (the same tax amount at each level of GDP) of $40 is imposed in this economy,the tax system:

A) is regressive.
B) is proportional.
C) is progressive.
D) may be either proportional or progressive.