(Advanced Analysis)Answer the Question on the Basis of the Following $\begin{array} { l } I _ { g } = \overline { I _ { g } } = 80 \\\mathrm {~S} = - 80 + 0.4 \mathrm { Y }\end{array}$

(Advanced analysis) Answer the question on the basis of the following information for a private closed economy,where I_g is gross investment,S is saving,and Y is gross domestic product (GDP) . $\begin{array} { l } I _ { g } = \overline { I _ { g } } = 80 \\\mathrm {~S} = - 80 + 0.4 \mathrm { Y }\end{array}$ Refer to the information.The equilibrium GDP will be:

A) $160.
B) $400.
C) $360.
D) $480.