(Advanced Analysis)Answer the Question on the Basis of the Following $\begin{array} { l } C = 40 + 0.8 Y \\t _ { g } = \overline { I _ { g } } = 40 \\X = \bar { X } = 20 \\M = \bar { M } = 30\end{array}$

(Advanced analysis) Answer the question on the basis of the following information for a private open economy.The letters Y,C,I_g,X,and M stand for GDP,consumption,gross investment,exports,and imports respectively.Figures are in billions of dollars. $\begin{array} { l } C = 40 + 0.8 Y \\t _ { g } = \overline { I _ { g } } = 40 \\X = \bar { X } = 20 \\M = \bar { M } = 30\end{array}$ The equilibrium GDP (=Y) in the economy is:

A) $200.
B) $245.
C) $320.
D) $350.