If interest rates rise, what happens to the debt service costs? A. Debt service costs will fall, since nominal interest rates will rise to keep the real interest rate constant. B. Debt service costs will rise, since nominal interest rates will rise to keep the real interest rate constant. C. Debt service costs will remain the same, since the amount of debt did not change. D. Debt service costs will reamin the same, since nominal interest rates will rise to keep the real interest rate constant