Which of the following average cost functions suggests the presence of a natural monopoly?

The Federal Reserve System is organized into ________ Federal Reserve districts

A) 6 B) 10 C) 12 D) 15 E) 50

A decrease in the interest rate results in

A. a greater opportunity cost of investment and so planned investment spending increases. B. a smaller opportunity cost of investment and so planned investment spending decreases. C. a smaller opportunity cost of investment and so planned investment spending increases. D. a greater opportunity cost of investment and so planned investment spending decreases.