Refer to the Diagram Below Wherein T Is Tax Revenues

Refer to the diagram below wherein T is tax revenues and G is government expenditures.All figures are in billions.In this economy:

A) tax revenues and government spending both vary directly with GDP.
B) tax revenues vary directly with GDP,but government spending is independent of GDP.
C) tax revenues and government spending both vary inversely with GDP.
D) government spending varies directly with GDP,but tax revenues are independent of GDP.