If an IRA Is a Variable-Rate Investment for 20 Years

Multiple Choice

If an IRA is a variable-rate investment for 20 years at rate r percent per year, compounded monthly, then the future value S that accumulates from an initial investment of $1,000 is . What is the rate of change of S with respect to r and what does it tell us if the interest rate is 7%? Round your answer to two decimal places. ​

A) The future value increases by approximately $866.86 when the interest rate increases from 7% to 8%.
B) The future value increases by approximately $803.06 when the interest rate increases from 7% to 8%.
C) The future value increases by approximately $1634.43 when the interest rate increases from 7% to 8%.
D) The future value increases by approximately $781.46 when the interest rate increases from 7% to 8%.
E) The future value increases by approximately $1565.73 when the interest rate increases from 7% to 8%.