Ms$.$ Smith borrowed $$1,250$ at a $11\%$ stated rate of interest and was to pay back the loan in $234$ monthly payments. What is her effective rate of interest?

A$)10\mathrm{.}56\%$

B$)21\mathrm{.}12\%$

C$)18\mathrm{.}96\%$

D$)22\mathrm{.}00\%$