The following table shows the relationship between the speed of a computer's CPU and its benefits and costs. Assume that all other features of the computer are the same (that is, CPU speed is the only source of variation), and only the CPU speeds listed below are available for purchase.CPUGHzTotal BenefitMarginal BenefitTotal CostsMarginal Costs2.0$1,000 $900 2.5$1,400  &1003.0 $300$1,200 3.5$1,900 &1,500 4.0$2,000  &400The marginal benefit of upgrading from a 2.0GHz computer to a 2.5GHz computer is:

If the economy falls into a recession, automatic stabilizers will cause:

A. tax receipts to fall and government spending to rise. B. both tax receipts and government spending to fall. C. tax receipts to rise and government spending to fall. D. both tax receipts and government spending to rise.

Which of the following machines has the lowest user cost? Machine A costs $15,000 and depreciates at a rate of 25%, machine B costs $10,000 and depreciates at a rate of 20%, machine C costs $20,000 and depreciates at a rate of 10%, and machine D costs $17,000 and depreciates at a rate of 11%. The expected real interest rate is 0%.

A. Machine A B. Machine B C. Machine C D. Machine D