You are planning on purchasing $$18,400$ worth of solar panels for your home that will last forever. These solar panels will save you $$140$ a month. What is the effective annual rate of return on this investment?

a$.$

$9\mathrm{.}13\%$

b$.$

$6\mathrm{.}76\%$

c$.$

$8\mathrm{.}39\%$

d$.$

$7\mathrm{.}83\%$

e$.$

$9\mathrm{.}52\%$