Katrina Jackson signed a simple discount note for $$9,000.$ The discount rate is $5\%,$ and the term of the note is $18$ months. What is the effective interest rate? $($Round to the nearest tenth percent$)$

Group of answer choices

$5\mathrm{.}4\%$

$6\mathrm{.}2\%$

$4\mathrm{.}9\%$

$3\mathrm{.}8\%$