In a Certain Economy, the Components of Planned Spending Are

In a certain economy, the components of planned spending are given by: C = 500 + 0.8(Y - T) - 300r
Ip = 200 - 400r
G = 200
NX = 10
T = 150
Given the information about the economy above, what would be the impact on autonomous expenditures of a one-percentage-point increase in the real interest rate?

A) Autonomous expenditures would increase by 35 units.
B) Autonomous expenditures would decrease by 70 units.
C) Autonomous expenditures would decrease by 35 units.
D) Autonomous expenditures would decrease by 7 units.