A higher discount rate applied to a given flow of returns in the future (e.g., $5,000 at the end of 5 years, $10,000 at the end of 10 years, $15,000 at the end of 15 years, etc.) will cause the present value of that flow to: a. remain unchanged if the future dollars do not change. b. increase c. decrease d. change in a direction that cannot be determined in general.