When applying the marginal principle, you should pick the level at which the activity's marginal benefit is less than its marginal cost

When disposable income is $8 trillion, consumption expenditure is $5 trillion; when disposable income is $5 trillion, consumption expenditure is $3 trillion. The MPC is

A) (5 - 3 ) ÷ (8 - 5 ) = 0.667. B) (8 - 5 ) ÷ (5 - 3 ) = 1.333. C) (5/8 + 3/5 ) = 1.225. D) (5 + 3 ) ÷ (8 - 5 ) = 2.667. E) (5 + 3 ) ÷ (8 + 5 ) = 0.615.

In the long run in the Keynesian model, a beneficial supply shock would leave the economy with a higher level of output, but also a ________ real interest rate and a ________ price level

A) higher; lower B) lower; higher C) lower; lower D) higher; higher