Interest rate $($with changing years$).$ Keiko is looking at the following investment choices and wants

to know what annual rate of return each choice produces.

a$.$ Invest $$420\mathrm{.}00$ and receive $$771\mathrm{.}98$ in $8$ years.

b$.$ Invest $$3,400\mathrm{.}00$ and receive $$12,729\mathrm{.}43$ in $18$ years.

c$.$ Invest $$31,465\mathrm{.}03$ and receive $$130,000\mathrm{.}00$ in $28$ years.

d$.$ Invest $$31,420\mathrm{.}72$ and receive $$1,400,000\mathrm{.}00$ in $45$ years.