National Bank offers a $6\%$ nominal annual interest rate, compounded monthly on its savings accounts, while Regional Bank offers the same effective annual return, but interest is compounded quarterly. What nominal annual rate does Regional Bank offer on its savings accounts?

a$.5\mathrm{.}88\%$

b$.,6\mathrm{.}03\%$

c$.6\mathrm{.}17\%$

d$.6\mathrm{.}50\%$

e$.,6\mathrm{.}75\%$