The Diagram Below Shows Desired Aggregate Expenditure for a Hypothetical

The diagram below shows desired aggregate expenditure for a hypothetical economy.Assume the following features of this economy: • marginal propensity to consume (mpc) = 0.80
• net tax rate (t) = 0.15
• no foreign trade
• fixed price level
• all expenditure and income figures are in billions of dollars. FIGURE 22-3
Refer to Figure 22-3.What is the marginal propensity to spend (z) in this economy?

A) 0.45
B) 0.48
C) 0.65
D) 0.68
E) 0.80